Obtains a transaction ID from R/3, and stores it in the class. R/3 3.0 onwards only.

Throws RFC_ERROR_INFO for RfcCreateTransID failure.

This function has to be called before each successful transactional RFC call. The transaction ID is stored inside the parent class (CRfcFunction::rfcTID) to be used for the subsequent call of a function module in R/3 using the transactional RFC interface, IndirectCall.

If an error occurs (e.g. communication error) during the call of a function module in R/3 via IndirectCall, the RFC client program has to reconnect the RFC connection and repeat the IndirectCall without creating a new TransID.

User is responsible for storing this transaction ID into permanent store when necessary.