Try this. I have not tested though, but is based on Roberts idea to work as you requested. Roberts idea will toggle the output everytime the switch will change state. Not on 0->1 only.

Code:
SwitchIn VAR PortB.0
OldState VAR BIT
SwitchState VAR BIT

OldState = SwitchIn
SwitchState = 0

Main:
  IF SwitchIn not = OldState THEN
    IF SwitchIn THEN
      SwitchState = SwitchState ^ %1  ' Switch has been toggled
    ENDIF
  ENDIF
OldState = SwitchIn
GOTO Main
Ioannis