OK, as some of you know I bought one of Jason's custom built camera arms a few months ago... Just recently I found a good deal on a original 501 head so I bought it. What do I need to attach the 501 head to Jason's camera arm?

Camera arm (1st picture): http://www.archerytalk.com/vb/showthread.php?t=558243

My 501 head: http://cgi.ebay.com/ws/eBayISAPI.dll...m=350138435747