SAP PI 7.3 and integration with Salesforce by SOAP API

Hi to all,

I am facing for the first time an integration project with SalesForce and our client decided to not buy the adapter so we have to work with the SOAP protocal and calls the SalesForce API. I have some questions that someone how do it before me maybe can answer and share his experince to understand the best way to approach this kind of integration:

- we have to manage many interfaces that has header and rows (like invoices, orders ..) and I am looking to know how to, if it's possible, update in a single call two different objects with the upsert() call ... it's possible? can you show me an example? otherwise how you manage flows like this? thanks for sharing this ...

- As I can seen around in the web to do operation with API calls we have to login to the salesforce system and get the SessionId and the URL where submit our data after ... I was thinking about concurrency, and parallel processes .. We have a Sandbox licence that permitted a number of 25 parallel process with the same login (sessionid?) .. How you face this? You do a logout at the end of every flows?

- What do you suggest to use? a BPM with a first login map and then the operation map (like invoices, orders ..) or a flow with one operation mapping and two or many mappings?

Thanks so much to share your knowledge about that.

Antonello