Well I didn't actually patch the module; it was Dimm who did the work that makes this possible. I figured out a few things along the way and to be honest it was pretty hard for me to get my head around at first.

I know people have been asking for this here and on drupal.org so hopefully it will save others the same confusion (or maybe cause more depending on how easy my tutorial is to understand).

Web design & ecommerce services.