process 2 input trees with a stylesheet

[Andy Fish]

Hi,

I would like my XSLT to be able to process 2 xml trees, one contains what
you would call the "main" document, and another one (the secondary one)
contains information that needs to be merged in.

the best approach I can think of is writing the secondary tree to a temp
file, passing the filename in as a parameter, and then using document() to
read this into the stylesheet.

Is there a better way to do this? I'm using .net but I want to minimise
implementation dependencies

TIA

Andy