Validation Identifier for Clearing Document

Hi everyone,

I need validation for clearing document. In our case, any customer invoice which amount (company code currency) is more than 7000 TRY and any cash receipt (amount is not important) should not be cleared. In my opinion, it can be done via "Manage Substitution/Validation Rules" app or "JOURNALENTRYVALIDATION" BAdI. But as far as I see there is no identifier for clearing document which is created after clearing such as accountingdocheader-transactioncode = 'FB1D'. Do you have any suggestions how should I proceed?

Best regards,