Flikweert,

Couldn't you pulse the pin. If you use a momentary switch you could, perhaps;

LED ON Mode: Pulse the Pin so that the duty cycle illuminates the LED. If the switch is pressed (gnd's the pin) the ON period of the Pulse will not readback as ON.

LED OFF Mode: Pulse the PIN so that the duty cycle does not illuminate the LED. The Switch performs as above.

Switch Debounce: Will have to be ratio-metric appropriate to PIN state.

glad it's your job.

regards,
p