This is very similar to my problem.
I had a custom payment module--Bank Transfer-- setup for a specific zone -- Indonesia.
The PEC process seems to be normal except that no PEC transaction is created. The resulting order is tagged using the customer payment module type, eventhough the order is from a different zone--US.
This is very confusing to customers because they have entered their CC information and correct address and no errors are presented to them. It then becomes odd to explain to them that their payment didn't go through.
Does anyone have insight, further comment or a fix for this?