> If I have understood the concept right, the following 
> expression should
> be ok:
> 
> (para | section)/title
> 
> should match both para/title and section/title.

It's allowed as an XPath expression but not as an XSLT pattern. The syntax
for XSLT patterns is (as it was in 1.0) a subset of the XPath expression
syntax.

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