What, like $25 isn't cheap enough? ok, so add a few hundred $ for a Lon controller (we used the CHC from HW) to enable/disable the unit. Sounds a lot more reasonable than either option offered by Mitsubishi.
I know this is an old thread but I had the same questions and it help me find some answers. It looks like the connector is now available from Mitsubishi as part no. PAC-715AD. Here's a link to the info they have available on their site http://usa.mylinkdrive.com/categorie.../show/909.html