Have you looked at Altova Diff Dog or <oXygen/> Diff Files?  I think there
was also a freebie at IBM's alpha works (don't have the full URL to hand
just now).  These variously let you treat out-of-order attributes as
equivalent, or treat the entire file as just a stream of characters,
ignore/consider white space, ignore/consider processing instructions and
comments, etc.
--
Hedley Finger
Training Content Developer and Tools Specialist
MYOB Australia Pty Ltd <http://myob.com/au>
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12 Wesley Court   Tally Ho Business Park   East Burwood VIC 3151 Australia
<mailto:hedleyDOTfingerATmyobDOTcom>
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