Character Encoding Option for File Upload?

If it isn't too much trouble, I was hoping to have the "file upload"
validator modified so that I can specify character encoding the same way
that I can while validating by URL.

I am trying to validate XHTML output produced by the Microsoft XML parser,
but it (apparently) always uses UTF-16 encoding for its 
output even when none of the additional characters are included.

I imagine that this would be much simpler than adding UTF-16 character
encoding :-).

Thanks in advance, and keep up the good work!

"Beware:
 At war
 Or at peace,
 More people die
 Of unenlightened self interest
 Than any other disease"
     - Octavia E. Butler, Parable of the Talents