I have a similar situation here, where I need to add COEP-VBUND into the extractor 0CO_OM_OPA_6. My solution is as followed:
1. In the structure ICORDCSTA1, add an append structure ZBWOM2_COBK_COEP
2. In the append structure ZBWOM2_COBK_COEP, add the field VFUND (with same type as in table COEP)
3. In RSA6, unhide the newly added field VBUND in the datasource 0CO_OM_OPA_6
4. Go to SE16 and table ROOSFIELD, display datasource 0CO_OM_OPA_6 with version 'A', and make sure the field VBUND has NOTEXREL = 'Y', since it's a standard SAP field from table COEP but not some customized ZZ field
5. Run RSA3 for 0CO_OM_OPA_6 and the VBUND is shown with data
Hope this helps some with the same problem.
Cheers, Ivy
