Convert image to WMF format in perl

Question

I have a website on a Ubuntu server and I need to be able to allow images to be downloaded in WMF format (they're stored as JPGs). ImageMagick can read WMF but not write. UniConvertor doesn't work properly (sk1libs error) so I thought I'd have a go at doing the conversion with GD but I'm having a little difficulty, mainly because I'm a bear of very little brain..

I've found the Image::WMF module so I can create a new image and save it in the right format, but how can I copy the image data into the new image object? Despite having a GD-like interface, it doesn't have a 'copy' function..

Image::Base::GD's man page says it can save as WMF but, if I try, I get an error when I call save()..

use Image::WMF;
use Image::Base::GD;
use GD::Image;

$file="test.jpg";

$wmf = Image::Base::GD->new(-file => $file);
$wmf->set(-file_format => 'wmf');
$wmf->save('test.wmf');

.. gives me Can't locate object method "wmf" via package "GD::Image"

I'm probably just being really stupid but if someone could point out the correct way (or a better way!) it'd be appreciated.