hi Bob,
The WS2000 is eight (8) channel only... if you've already used (8) then you won't be able to set a 'reset' switch.
I'm assuming you're still using the iX12.
You need to pick a switch that is not being used, and you need to pick a channel (on the iX12) that is not being used... Aux1 - Aux7.
Then, on the iX12, use the "Model Setup | Channel Assign" to put your selected switch ON your selected channel.
In your manual this is covered on page 171, and 213-ff.
Once the switch is setup on the appropriate Aux channel, then make sure the iX12 is ON and Bound to the WS2000. Enter the Select Control Editor and find the 'reset' channel. Use the Spektrum Receiver (7+ch) as a template, and save it to another name. Mine is called "Generic Plane Sim II".
The first seven channels should be set (little x on far right).
Scroll down to the bottom and search for the 'Reset' channel. Click the 'unassigned' input bar, and when the 'Input Detection' panel comes up, click your selected switch on the iX12. In my case I chose switch (B) just for fun.
Then save the Radio Profile. Reset has two functions. (1) momentary switch is the 'Reset' you're looking for... resets after a crash, do this quickly on|off... (2) hold the 'reset' switch 'rewinds' the flight so that you can play it forward again, or start from that point... hold the switch on for your desired time, then release it.
Just to sum up the big picture... setup a switch on one of your Aux channels on the iX12. Use the Input Detection on the Controller Editor to setup your switch on the iX12 to the Radio Profile channel 'reset'.
PS edit: if you didn't use the Spektrum Receiver (7+Ch) as a template, you may not 'see' the Radio Profile 'Reset' channel.
PSS edit: the reason I chose switch (B) is that I also use switch (B) for mode... SAFE | AS3X. I use switch (B) position (2) for 'Reset', pos (0) for SAFE, and pos (1) for AS3X. Again pos (2) momentary is 'reset', and pos(2) hold is for 'rewind'. In other words, switch (B) in my transmitter functions (at the same time) as input for the Radio Profile channel 'mode', and Radio Profile channel 'reset'.
marcus