Relevant field for printout /external send

Hi Gurus.

I'm facing following issue:

I have two message for PO, ZPNE- for print output and,  ZPPC - External send.

I have deactivated EKPO-ELIKZ field in fields relevants to printouts of changes (configuration).

So whether  a PO has a change in the  field EKPO-ELIKZ,  messages shouldn't be executed.

That's working good for the ZPNE message,  but not for ZPPC message which is being executed and  is sending the PO to vendors.

The behavior for ZPPC  is not required How can I avoid that?

I really appreciate your advices.

Juan B.