Hello Karthikyan,
We use Proxys to connect PI and ECC. The flow is an XML file. Paste in a directory, and the system take it and send it to ECC via proxy, and on the proxy class, we implement a method which call a specific FM.
Maybe the proxy use transactional RFC i dont know. But it is not the first time we created data with this kind of flow, and it's always work.
Maybe a "WAIT" gonna work, i have already thought about that but i really dont understand why WF-BATCH interfere to my business partner creation and modification... 