Signing XSLT for Word 2007?

[p0]

Dear all,

It seems like Word 2007 does not like the use of scripts in XSLTs.
Something which is understandable. However I don't get the 'error'
message that is returned:

"The XSL Transformation (XSLT) file that is applied to this document
contains scripts or references to other documents, but it is not
signed. Word will apply the XSLT file, but the scripts or references
will not run."

So according to this, it must be possible to sign the XSLT somehow. My
question is, how?

TIA,

Yves

P.S.: For those of you wondering what I mean by script, see the
following example:

<ms:script language="C#" implements-prefix="usr">
<![CDATA[
public string test( string str )
{
return str;
}
]]>
</ms:script>