This is the button script that I use to turn the cross-hair on / off from the same screen button (I am using Output #5 to switch the device)
If IsOutputActive(OUTPUT5) Then ‘Check to see if its on
DeActivateSignal(OUTPUT5) ‘Its on so turn it off
Else
ActivateSignal(OUTPUT5) ‘Its off so turn it on
End If
(If it's any help, further detals are here
http://www.cooperman.talktalk.net/files/17.htm)
Tweakie.