Open up the file and look for the declaration line.

$isxml = 0;
while(<HANDLE>) {
    if($_ =~ /.*xml\s+version/i) {
        $isxml = 1;
        last;
    }
}

if($isxml) { # xml file stuff here }
else { # not xml file stuff here }
[download]

This was written in a hurry and not tested (I need to run to a meeting ;)) but it should be enough to start with

Update: Rereading this post-meeting I see I missed the question altogether.... davorg gave the right answer ;)

$japh->{'Caillte'} = $me;