Yes it is possible if you modify the code of the processor. At the moment the path is hardcoded on line 126, it can be made so that if the http:// string is present in the xml / xsl file path then said path is not modified.
It would go something like this:
If http:// is present in $xml then do nothing, otherwise, $xml = $path.$xml
if http:// is present in $xsl then do nothing, otherwise, $xsl = $path.$xsl

The modification necessary should be around line 126/127

Hope it helps,