Raw part of response:
 
HTTP/1.1 200 OK
Content-Length: 2472
Content-Type: multipart/related; boundary="----=_Part_209_1705370022.1700121816544"; type="application/soap+xml"
Date: Thu, 16 Nov 2023 08:03:36 GMT
Set-Cookie: JSESSIONID=2011F5CA9966037AB8E4853C0DF30491; Path=/; HttpOnly
Set-Cookie: ARRAffinity=7ac5e33e7f20d9f741909dd6f767c2a893ddda7a3da0e78657ba93a8273151ba;Path=/;HttpOnly;Secure;Domain=cms-psecsire-tst1-b2b.azurewebsites.net
Set-Cookie: ARRAffinitySameSite=7ac5e33e7f20d9f741909dd6f767c2a893ddda7a3da0e78657ba93a8273151ba;Path=/;HttpOnly;SameSite=None;Secure;Domain=cms-psecsire-tst1-b2b.azurewebsites.net
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
X-Content-Type-Options: nosniff
Content-Security-Policy: frame-ancestors 'self'; default-src 'self'

------=_Part_209_1705370022.1700121816544
Content-Type: application/soap+xml; charset=utf-8
Content-Id: <soapPart@cms.org>
Content-Transfer-Encoding: binary

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope"><env:Header><ns2:Messaging xmlns:ns2="http://docs.oasis-open.org/ebxml-msg/ebms/v3.0/ns/core/200704/" xmlns:ns3="http://schemas.xmlsoap.org/soap/envelope/" env:mustUnderstand="true"><ns2:UserMessage><ns2:MessageInfo><ns2:Timestamp>2023-11-16T08:03:36.525Z</ns2:Timestamp><ns2:MessageId>2856004f-cfe0-42c9-8524-d5c62edf712a</ns2:MessageId><ns2:RefToMessageId>091b6517-1320-437a-ad33-31ec01f23287</ns2:RefToMessageId></ns2:MessageInfo><ns2:PartyInfo><ns2:From><ns2:PartyId type="urn:oasis:names:tc:ebcore:partyid-type:iso6523:0088">10XPL-TSO------P</ns2:PartyId><ns2:Role>MOP</ns2:Role></ns2:From><ns2:To><ns2:PartyId type="urn:oasis:names:tc:ebcore:partyid-type:iso6523:0088">19XPLTEST03DSO13</ns2:PartyId><ns2:Role>DSO</ns2:Role></ns2:To></ns2:PartyInfo><ns2:CollaborationInfo><ns2:AgreementRef>Compression</ns2:AgreementRef><ns2:Service>MarketMessaging</ns2:Service><ns2:Action>PeekMessage.Reply</ns2:Action></ns2:CollaborationInfo><ns2:PayloadInfo><ns2:PartInfo><ns2:PartProperties><ns2:Property name="MimeType">application/gzip</ns2:Property><ns2:Property name="CharacterSet">utf-8</ns2:Property><ns2:Property name="PartID">MSG.PEK20231116080336525.xml.gz</ns2:Property></ns2:PartProperties></ns2:PartInfo></ns2:PayloadInfo></ns2:UserMessage></ns2:Messaging></env:Header><env:Body/></env:Envelope>
------=_Part_209_1705370022.1700121816544
Content-Type: application/gzip
Content-ID: <MSG.PEK20231116080336525.xml.gz>
Content-Transfer-Encoding: binary
Content-Disposition: attachment

 US<BS  (Binary content)

XML part of response:

<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
  <env:Header>
    <ns2:Messaging env:mustUnderstand="true"
      xmlns:ns2="http://docs.oasis-open.org/ebxml-msg/ebms/v3.0/ns/core/200704/"
      xmlns:ns3="http://schemas.xmlsoap.org/soap/envelope/">
      <ns2:UserMessage>
        <ns2:MessageInfo>
          <ns2:Timestamp>2023-11-16T08:03:36.525Z</ns2:Timestamp>
          <ns2:MessageId>2856004f-cfe0-42c9-8524-d5c62edf712a</ns2:MessageId>
          <ns2:RefToMessageId>091b6517-1320-437a-ad33-31ec01f23287</ns2:RefToMessageId>
        </ns2:MessageInfo>
        <ns2:PartyInfo>
          <ns2:From>
            <ns2:PartyId type="urn:oasis:names:tc:ebcore:partyid-type:iso6523:0088">10XPL-TSO------P</ns2:PartyId>
            <ns2:Role>MOP</ns2:Role>
          </ns2:From>
          <ns2:To>
            <ns2:PartyId type="urn:oasis:names:tc:ebcore:partyid-type:iso6523:0088">19XPLTEST03DSO13</ns2:PartyId>
            <ns2:Role>DSO</ns2:Role>
          </ns2:To>
        </ns2:PartyInfo>
        <ns2:CollaborationInfo>
          <ns2:AgreementRef>Compression</ns2:AgreementRef>
          <ns2:Service>MarketMessaging</ns2:Service>
          <ns2:Action>PeekMessage.Reply</ns2:Action>
        </ns2:CollaborationInfo>
        <ns2:PayloadInfo>
          <ns2:PartInfo>
            <ns2:PartProperties>
              <ns2:Property name="MimeType">application/gzip</ns2:Property>
              <ns2:Property name="CharacterSet">utf-8</ns2:Property>
              <ns2:Property name="PartID">MSG.PEK20231116080336525.xml.gz</ns2:Property>
            </ns2:PartProperties>
          </ns2:PartInfo>
        </ns2:PayloadInfo>
      </ns2:UserMessage>
    </ns2:Messaging>
  </env:Header>
  <env:Body/>
</env:Envelope>

Rozpakowany załącznik:
<soapenv:Envelope xmlns:urn="urn:cms:b2b:v01"
  xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope">
  <soapenv:Header/>
  <soapenv:Body>
    <urn:PeekMessageResponse>
      <urn:MessageContainer>
        <urn:DocumentReferenceNumber>2856004f-cfe0-42c9-8524-d5c62edf712a</urn:DocumentReferenceNumber>
        <urn:Payload>
          <msg_R_1:OperationResult xmlns:msg_R_1="urn:pl:oire:message_R_1"
            xmlns:tech="urn:pl:oire:technical"
            xmlns:bdt="urn:pl:oire:businessDataTypes">
            <msg_R_1:Header>
              <tech:MessageId>2856004f-cfe0-42c9-8524-d5c62edf712a</tech:MessageId>
              <tech:SenderMessageId>4a9a467f-ca7c-4d32-a9a7-53d87bd66525</tech:SenderMessageId>
              <tech:MessageType>R_1</tech:MessageType>
              <tech:MessageTypeResponsibleOrganization>x</tech:MessageTypeResponsibleOrganization>
              <tech:MessageTimestamp>2023-11-16T08:03:30</tech:MessageTimestamp>
              <tech:PhysicalSenderId>10XPL-TSO------P</tech:PhysicalSenderId>
              <tech:PhysicalSenderIdResponsibleOrganization>305</tech:PhysicalSenderIdResponsibleOrganization>
              <tech:JuridicalSenderId>10XPL-TSO------P</tech:JuridicalSenderId>
              <tech:JuridicalSenderIdResponsibleOrganization>305</tech:JuridicalSenderIdResponsibleOrganization>
              <tech:PhysicalRecipientId>19XPLTEST03DSO13</tech:PhysicalRecipientId>
              <tech:PhysicalRecipientIdResponsibleOrganization>305</tech:PhysicalRecipientIdResponsibleOrganization>
              <tech:JuridicalRecipientId>19XPLTEST03DSO13</tech:JuridicalRecipientId>
              <tech:JuridicalRecipientIdResponsibleOrganization>305</tech:JuridicalRecipientIdResponsibleOrganization>
            </msg_R_1:Header>
            <msg_R_1:ProcessEnergyContext>
              <tech:BusinessProcess>CK1005</tech:BusinessProcess>
              <tech:BusinessProcessTypeResponsibleOrganization>x</tech:BusinessProcessTypeResponsibleOrganization>
              <tech:SenderBusinessRoleIdentifier>CK0083</tech:SenderBusinessRoleIdentifier>
              <tech:SenderBusinessRoleResponsibleOrganization>x</tech:SenderBusinessRoleResponsibleOrganization>
              <tech:IndustryClassificationId>23</tech:IndustryClassificationId>
              <tech:BusinessProcessMessageType>2.1.1.2.</tech:BusinessProcessMessageType>
            </msg_R_1:ProcessEnergyContext>
            <msg_R_1:Payload>
              <msg_R_1:Result>
                <msg_R_1:ProcessInstanceId>157be875-17ce-4b4e-b657-65473ac824c2</msg_R_1:ProcessInstanceId>
                <msg_R_1:ErrorCode>CA001</msg_R_1:ErrorCode>
              </msg_R_1:Result>
            </msg_R_1:Payload>
          </msg_R_1:OperationResult>
        </urn:Payload>
      </urn:MessageContainer>
    </urn:PeekMessageResponse>
  </soapenv:Body>
</soapenv:Envelope>