Norm Walsh has a combined schema for the two, which must work
(I've not
actually read his schema) by conditioning validation on the root
version attribute.
Actually, a valid XSLT 2.0 stylesheet that specifies version="2.0" is a
valid XSLT 1.0 stylesheet, because of forwards-compatibility mode.
Though in fairness, an XSLT 2.0 stylesheet that specifies version="3.0" and
uses as-yet-uninvented features of XSLT 3.0 will not get through the
published schema for XSLT 2.0.
Michael Kay
http://www.saxonica.com/