Internal Supplier Profile Change Approval - Tax Registration Number changed

Summary:

Is there a way to trigger approval if the Tax Registration Number is changed?

As per documentation, approval rules can be setup for changed taxpayer id, however we want to trigger approval also for changes in Tax Registration Number. This is stored either in the Transaction Tax tab → Tax Registrations:

or it is stored in Addresses → Transaction Tax → Tax Registrations:

We've already checked the IntProfileChangeRequestApproval in BPM, but I cannot find a field in the task rules related to Tax Registration Number.

Thank you.