Converting EDI to WebMethods

We have currently converted our EDI from one translator to webMethods. During the processEnvelope evaluation one of our trading partners orders are rejecting due to the fact they are sending a PID04 with no PID05. This is not a standard way of sending the data, but I can not get them to change their system and the old translator would let this condition slide. Is there a way to get webMethods to act similar so I can finally get the last trading partner converted.