Truncation of SWIFTMT940 "Bankreferenz" field in Tag :61

We've let SAP know about the SWIFT_MT940 subroutine of RFEKA400 truncating the BANK_REFERENZ field of the :61 tag in an unfortunate way (so that you can't see the numeric 'NNN' portion of the field on the screenwhen you run RFEBKA00.) If SAP doesn't agree to fix the problem, does anyone see/have a way to do a supportable enhancement/mod that doesn't involve client copies of programs and structures? The relevant code in the subroutine occurs right under the comment:

*Subfeld 8: Baknreferenz