We ended up enhancing RP_READ_T100 to replace things passed in as bplans and replace with the bplan's text. This is a sloppy way of doing it, but SAP doesn't really provide customer's a way to customize these messages.
Interestingly, there is some inconsistencies as to how they handle ess messages today, some have the bplan in the message others have the text.
I pointed this out in an OSS message, but correcting the inconsistencies would have been quite a task.