HTTP Request; Issue with post request & sap B1 service layer

I would to fo the authentification to SAP B1 with dynamic password received in the payload.
When i check available nodes to authentificate to SAP B1 Service layer, I found that the password is static:

However, I don't know the password from the begging. That's why I tried to use the node "HTTPRequest" as shown below:

I prepared the body of POST Request and I put it in msg.payload but I Got an error" 312;failed to connect to SLD"

Can you help me to solve the issue or there is another node used to authentificate to a restful api and get session ID?

Best Regards,