I have never done it...
Ive scanned the helms manual on how to do it.
Hosted on crappy Yahoo photos....
http://f1.pg.photos.yahoo.com/ph/pmi...&.dnm=23ce.jpg
http://f1.pg.photos.yahoo.com/ph/pmi...&.dnm=d85d.jpg
http://f1.pg.photos.yahoo.com/ph/pmi...&.dnm=684f.jpg
If you cant get them to work, or if theyre too small to read, PM me your email address and I'll forward the directions to you.