Creating a user defined field

Dear Experts/Gurus,

I have a problem about creating UDF (user defined field) in process external bank statement in SBO 2004A SP 00 PL 41 that I want to use to develop a reconciliation report that has been 2 weeks not finished yet. The customer want the balance of the last month must be recorded in the table (OBNK). Then I have tried to add a UDF in category payment --> title but it only appears in incoming payment. Could it be possible to add a user defined field in the process external bank statement ? if yes, in what category I have to add the UDF ? I appreciate your answer. TIA.

Rgds,