How close/far are they? Are you using LEAP/PEAP/static wep? If so, remove that and try again. Simplify, then complicate and back it off half a turn :) Anywho, you should be able to put a very large number of aps on the wired lan with the same ssid. Y...
If it were me, I would NAT my outbound traffic prior to it hitting PIX or NAT the traffic inbound coming from the far end after it hits your PIX. I have had issues trying to make this work by natting towards the ipsec interface.HTH.
One of the last posts about STP is correct unless you use backbonefast/uplinkfast. Are these core or distribution devices? STP uplinkfast/backbonefast work like this: Let's say your 6509s are switches a/b. I did not catch whether or not you have dual...