Yes, there's no reason why you can't use them together.
Except that it worries my slightly that you're proposing to make architectural choices about the design of your application with such a weak understanding of the roles of the component technologies. Are you sure you are ready to make decisions without doing a lot more learning first?
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference