how to delete ME22N and ME21N custom error mesagges?

Some time ago one of our clients required some custom filters for me21n/me22n, so we ended copying me_process_po_cust into zme_process_po_cust, and implemented the method process_items.

There we used the include mm_messages_mac to use mmpur_message to enter the new error messages into me21n/me22n.

The error messages work perfectly, but we are having problems with mmpur_remove_objects_by_id (actually, we have a declared context, so we are using mmpur_remove_objects_by_context, but for this question by_id works fine).

The problems we are having is that so far we are unable to get the correct IDs to erase,We've been dabling into the objects structure for two days, and we are not closer to finding out how to get them.

So, we are either needing a way to get the messages IDs for the item being evaluated right now, a way to get the list of IDs with some way to relate them to the item being evaluated or a way to refresh the error messages before procesing the new errors without knowing the actual IDs.

Any kind of pointers, even if they don't solve the problem and require further investigation, will be really apreciated.