The adapter mentioned in the other thread might work...I have used tualatins with that adapter on regular socket 370 boards
$30 bucks here
http://www.strattoncomputer.com/370gusoc370a.html
but compgeeks used to have em for $10...maybe they are out right now though cuz I didnt see any there.
But with it being an HP there is a slight ? mark as to whether it would work anyway cuz they sometimes cripple those OEM boards so that they cant be upgraded much.
Thats a good price...have you tried selling on anadtech forums?