Dynamic Filename doubt!!!

Hi Experts

I have a bypass scenario where I need not do any transformation to the file but need to change the filename scheme.

The sourcefile name is XYZ.txt whereas the target needs to be <IDOCNUM>_X_Y.DAT

As of now we have used a java mapping to achieve this but I was looking out for something simpler.

I mean can we straighaway catch the IDOCNUM(comes in source payload) and use it for filename scheme?

Regards

Soumen...