How to get SESSION ID

Hi Experts,

Could please me help me on this scenario as below.

ECC-- SAP PI -- 3rd Party

Sender is a Proxy, Receiver is a SOAP

1. Login into 3rd Party and need to get the SESSION ID with valid user name and password

2. Need to pass the SESSION ID as SOAP Header with actual payload.

I came to know that this can be done at mapping level using UDF to get the Session ID.

I have gone through the Bhavesh Kantilal Blog.

Could you please provide help on this.

Thank you in advance.