XSLT 2.0
You can edit XSLT 2.0 Stylesheets in XMLBlueprint. Make sure your XSLT Stylesheet starts with:
Running XSLT 2.0 Stylesheets
MSXML (XMLBlueprint's default XSLT processor) does not support XSLT 2.0. Instead, you can use the Saxon 8B processor by selecting Tools > Saxon 8B.