I have seen pics of the attach mate, but do not know anything about it.
Have you considered making your own wooden dummy?
You can buy plans on eBay sometimes, or get them free here:
http://www.wckfc.com/news/dummy/
You can make a pvc one like this also:
http://karateconnection.com/dummy.htm
Also, you can make a better dummy out of two old tires and some carriage bolts. A round tire constitutes the center mass. Now cut another tire in half and carriage bolt each end (4 corners) to the top to make the head. For the extremities (2 arms
and two legs) cut 4 half tires and bolt them to the center main tire in the natural shoulder and hip points. Put this up on an "easel" or post made of wood and enjoy.
pressureguy