styling a stylesheet

hello, i'm after a bit of help,

i'm trying to produce an xsl stylesheet by styling another xml
document with an xsl stylesheet, now, when produced directly, the
intermediate stylesheet appears ok. But when used 'inline'
firefox says the stylesheet isn't valid, i was thinking any xml file 
with a stylesheet should just be 'seen' as the result of applying its 
stylesheet, so what i want to know is, is this unreasonable, is it just 
that firefox ignores stylesheets on stylesheets, or should it work and i 
must be making a mistake.

hope this makes sense, thought of many uses for this and have googled 
but now don't want to waste any more time, if this is not supported.

simon, thanks in advance.