xsl:include href - relative to document root?

MSXML4
ASP

We're using ASP to render XML files using XSL style sheets.  In a
style
sheet I'm trying to understand the different ways to xsl:include
another
style sheet.  Is there a way to have an xsl:include href refer to a
file relative to
the webserver's document root?  From the documentation I've read
it seems that the only way the href can be specified is either

  1. absolute - which for us means starting with a drive letter and
                         continuing with a path to the file, or
  2. relative - starting with "../" assuming the current position is
                      the directory where the xsl file being rendered
is.

Is there another way?

Thanks.

Hardy Merrill