Problems with 2LIS_11_VAITM extractor

Here's what I've done so far:

1) Extended the 2LIS_11_VAITM extractor to include two new custom partner types.

2) Added code in module RMCSUZ10 to populate the two new partner types based on the PARVW value on the VBPA table.

Everything is working fine EXCEPT the RMCUSZ10 module is not being executed. I put a breakpoint at the top of the module and tested the exractor via RSA3 and the breakpoint is never hit. Therefore my two new partner types in VAITM are not being populated.

What configuration or setup am I missing that's keeping this module from being invoked?

Thanks!