Problems loading XSLT stylesheets in web browser

Dear all,

as Mozilla web browsers are able to render XML with XSLT directly, I 
copied Norman Walsh's XSL DocBook stylesheets to our web server. But 
when I try to open a DocBook document, I get the following error message:

"Error loading stylesheet: An XSLT stylesheet does not have an XML mimetype:

http://url_of_our_web_server/Style/xsl/VERSION"

I think that it has something to do with the fact, that VERSION has no 
file extension like .xsl, so our web server cannot send the correct mime 
type to the browser.

Does anybody knows a way to solve this issue?

Cheers
BP