RE: Calling subdocuments with processing directives

>  From what you say, it should do exactly what I expected - 
> but the key in the top document does not appear in the key 
> set. Tomorrow I'll knock up a test case (it is currently 
> passed my bedtime).

You need to remember that the key() function searches within the document
specified in the third argument, or in the document containing the context
node if there is no third argument.

Michael Kay
http://www.saxonica.com/