Transform program for incoming XML message via Integration Broker

Hi PeopleSoft Integration Specialists,

I have an incoming message to my gateway, everything is working great but I have a new requirement to validate and trim down if necessary on of the field values in that message before the value is loaded into our temporary tables. What would be the best way to do it? And the most important question is how do I do it?

So when the message comes in if the value in the filed is too long when handler loads it into temp tables only 10 characters is loaded because field length is 10. However I would like to verify field length before it's loaded and trim it exactly how I wanted before it's loaded.