call a Perl function from XSL?

Is it possible to call a Perl function from within an XSL document?  I have a URL that needs to be encrypted using MD5, and I have a nice Perl module that does the en/de-cryption.  However, the URL doesn't get created until the XSL stylesheet is called.  Therefore, I'd like to be able to call the encryption function just before the URL is assembled.  
I'd really appreciate any direction as to where to look to find info on how to do this. . . I've read through the FAQ, and it mentioned doing something similar in Java, but I need to use Perl.

Thanks.

Tricia Ballad


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list