If you don't want to attach them using the keyring, you could pick one of these up on eBay and attach it using this...
http://cgi.ebay.com/MINI-TRIGGER-SNAP-KEYRING-FOR-COACH-BAG-BRIEFCASE_W0QQitemZ320205290770QQihZ011QQcategoryZ11481QQtcZphotoQQcmdZViewItem
I don't even bother trying I take the the key ring off and slip the charm onto the ball chain, I also purchased a spring/trigger clip which I attached to a key ring and clip my keys inside the bag to the D ring.
Has anyone noticed the two "BRASS" key fobs in the new catalog? One is a pierced Coach medalion, the other has multiple padlocks, they come with a spring/trigger clip!!!!!
If you don't want to attach them using the keyring, you could pick one of these up on eBay and attach it using this...
http://cgi.ebay.com/MINI-TRIGGER-SN...hZ011QQcategoryZ11481QQtcZphotoQQcmdZViewItem