How to use a Mobile Doctype in my XSLT file which outputs as XML

[deucalion0]

I have been trying for a long time to use a mobile Doctype in my XSLT file like so:

    <xsl:output method="xml" omit-xml-declaration="yes" 
   doctype-public="-//WAPFORUM//DTD XHTML Mobile 1.0//EN" doctype-system="http://www.wapforum.org/DTD/xhtml-mobile10.dtd"/>

but when I do this my sites layout goes all crazy which you can see here. I need to validate my mobile site at this site and it will not detect the Mobile doctype unless I output as XML, which as you can see messes up my page. Can anyone explain why this is happening, and maybe show me how to do this, or explain why it is happening?

Many thanks!!!