How to find inbound document's FM/BADI enhancement options?

[former_member188321]

Hi Experts,

The data comes from CRM as a BDoc. when a campaign is saved in CRM, a BDoc 'MKTPL_MKTELEM' is triggered by Standard code which reaches ECC and update few standard fields in PS - Project/ WBS element. This is SAP's standard feature. Now there is a field in CRM Campaign, which exists in the mentioned BDoc message as well. This field value should populate in a Z-field at WBS element.
Question is, where to map these BDoc field to Z field? How does ECC knows which field of BDoc message should be populated to a field in WBS element? Is there any FM/Exit/ BADI for this?
Since this is generic question on a standard feature of PS update, you may not need to look into DCM specifically.
Regards,

[former_member188321]

Experts, Can anyone answer this? Regards,

[Jelena]

Does Google 'BDoc user exit site:sap.com' not provide any information? Is debugging also not available?