Session ID as Token and this Token pass as SOAP Header parametern with actual Payload

Hi All,

Could please me help me on this scenario as below.

Proxy -- SAP PI -- 3rd Party

Sender is a Proxy, Receiver is a SOAP

before Sending the actual payload, i need to get the session ID using the login credentials into that 3rd party, and that session id need to pass in SOAP header with actual payload.

Thank you in advance.