document() function query

Hi guys,

Apologies if this is documented somewhere that I've failed to find 
(or has been discussed here in the past) but can anyone tell me if 
the implementation of the XSLT document() function within Mozilla 
supports access to files from a server other than the one hosting the 
referring XSLT file?  I'm trying to include a dynamic reference to an 
external datasource and I am getting nothing (null string) back.  The 
URI works fine if I render it as text via the XSLT and then copy and 
paste what is displayed into the browser's (Firefox, Mac OS X 10.3.7) 
location field.  Works fine too if I save that returned file to my 
server and then reference that within the XSLT, so it looks like the 
external call is failing.

-Steve