Dear Voodoo,
A couple of threads that may help:
http://www.somersoft.com/forums/showthread.php?t=621&highlight=vending
http://www.somersoft.com/forums/showthread.php?t=6380&highlight=vending
http://www.somersoft.com/forums/showthread.php?t=11077&highlight=vending
Cheers,
Sunstone.