Synchronous BAPI calls to R/3 from XI

We are trying to execute a BAPI call in R/3 via XI. Here are the details:

Backend - R/3 IDES 4.6C

BAPI - BAPI_MATERIAL_AVAILABILITY

XI 2.0

XI adapter - RFC adapter

The RFC adapter is configured and executing the BAPI call successfully and returning the correct data. However, XI is not processing the results and sending it back to the source which made the synchronous request.

My questions are as follows:

1. Anyone here actually executed a synchronous BAPI using RFC adapter?

2. If so, what is it that we need to do to send the XML message back to source?

BTW, I have tried another BAPI and same result.

Many thanks in advance.

SR