Hey there.. I've been selling Cams.com myself, ever since I started In porn actually
I do about 1:120-140 with them right now. Personally I dont care to much about the cams in a box thing. Try to use some of their more simple gadgets.. They have great Iframes with direct links to live camshows. they also have a livecam window to put on your site with an online performer.. So just keep at it, try some different things and you'll get it to convert soon
Check out one of my sites for inspiration
www.gratiswebcamsex.dk