Here's the frame stiffner/switch mount that came with my 600NSP. The problem is bolts to the front of the frame under the canopy per the manual. Not sure if it will mount elsewhere but that was void the point for me...
http://www.helihobby.com/html/trex_n...#PARTHN6087-00

Here's a couple options from HeliHobby. I have no clue how to use them I have a round pin flag switch I plan to use.
http://www.helihobby.com/html/freya_...PARTMJP-HB1800
http://www.helihobby.com/html/rc_hel...tml#PARTDUB203

Not sure how this one works.. lol I guess you drill your own holes for the switch?
http://www.helihobby.com/html/freya_...PARTMJP-HB1799

You can always call HeliHobby and ask the speak to the tech. Maybe she knows which will work with what switch best. Anyway I had planned to use one of these and just drill a hole before I decided to just go with the Fromeco Arizona Regulator and the pin flag switch.