validating php

Still waiting for one of you guys to come up with a solution to making php files validate without removing the encoding line of code......... its driving me barking mad!!!
In the end I have had to change the file to an html extension and insert I Frames linking to the php files, not pretty but it works.
It validates for now but we all need a solution if we are to improve standards and make xml applications work otherwise the lazy will avoid it like the plague
If I crack it I'll be sure to tell the world.
Keep up the good work

Paul