How to do to add a specific BAPI WBS Check betteen 2 systems via ALE

I am on the module TRAVEL MANAGEMENT (FI-TV) into the sap system DTM version ECC5 (for expenses). I wish communicate with the SAP system R/3 DGI version 4.6C via ALE and BAPI.

When I create the expense in DTM, I put a WBS and I want to do severals checks via ALE into the system DGI.

I have implemented the note 516109 into DGI to instal the bapi "BAPI_PROJECT_EXISTENCECHECK".But the link doesn't work from DTM to DGI.

Please could you help me ?

Other point : How to do to add a specific Bapi to check

WBS? I didn't found USER EXIT.

Thank in advance.

Odile Dougnac