After a lot of good coffee an better guinness (just joking) and after spitting through some massive ammounts of docs, we finally found the right Apache module calls.

use Apache;

my $r = shift;
my $uri = $ENV{REQUEST_URI};
my $path = $r->lookup_uri($uri)->filename;
[download]

note: we couldn't use the 'pwd' because we use this as a default in the apache config:

DirectoryIndex    index.html index.mpl /cgi-bin/listing.mpl

so pwd would be the cgi-bin directory and not the requested directory

udpate (broquaint): s|<(/)?pre>|<${1}code>|g