Originally Posted by Maxwell
I'll have to look in the manual and see if they offer a part number for the magnet
This is not an official part, but should do the trick. The hole is 5/16" which fits the 7.7 mm Schraeder valve dimension nicely. It is a neodymium magnet so it is as strong as you are going to get. $4.25 plus shipping at this supplier:
http://www.kjmagnetics.com/proddetail.asp?prod=RX054