Adding Aux switch GT2 TX

[Dougelove]

Hi all,
I have just upgraded my beast, all ally 32 Losi LST to 2.4ghz and as per title, I would like to add an aux switch to my HK-GT2 TX. I would like to use reverse sometimes on my LST as it is useful. I have it plugged into CH3 on RX but now need to switch it. Any ideas? Much appreciated.
Why have a 3ch RX paired with a 2ch TX?!!
Cheers
Doug

[D20MCK]

You need a different transmitter with 3 channels to make that work, it's impossible with your setup at the moment.

[Dougelove]

Ok thanks. Now I need a 3ch TX. Any offers??