ok I understand what you are saying.
However as Customs/Risk Management is not a part of the solution, we will not activate MM0C for any of the movement types. In the absence of that I don't think MM0C BADI will be called at all.
So we may have to select another position within the code/application to call the MM0A/MM0B FM. May be we use a BADI within the Transfer Posting Application (MIGO transaction) and call MM0A FM to create Customs Document in GTS (if feasible). If we are successful in creating the Document in GTS and perform License checks, then based on response message of FM we can stop the transfer posting. Requirement is to check whether project to project transfer is covered under an existing license. If not, then stop the transaction until license is sorted out.
This is something we'll have to try and see if it works.