Tax Rule using Tax Reporting Code not working

HI,

could use some help:

I created a Tax Reporting Code (Reporting Usage = Tax Determination).

I created a Rule,(Tax  Determination = Supplier Reporting Code) and appropriate value

I added the Tax Reporting Code to the supplier site

I created a manual AP invoice for the supplier

No tax category defaults (although I am able to manually select the tax category)

Any ideas why this Rule is not working?

Thanks for any help.