ken is on point with the wayne-dalton keychain. you can use their keyfob with their secondary controller. it would be much easier to seal that in plastic than a whole ha09.
haven't tried these yet but check out these z-wave pool/spa controls/contoller:
http://www.intermatic.com/Default.asp?acti...d=107&did=4
http://www.intermatic.com/Default.asp?acti...d=111&did=4
let me know if you try them out. i am curious if they are full z-wave compliant devices which can be added into any z-wave network or a bastardized version like harmony is doing with their 890 and 1000 line remotes to extenders where they can only operate to each other.