CH7_Opt only above 1800 possible?

Hello,

my RC gives at RC7 a maximum value of 1780. I would like to use the CH7_OPT of a function control. Is it possible, to activate the function at a value e.g. bigger 1500?
What have I to parameterize to change the function activation value?

Thanks!

You could also adjust the maximum travel on your RC channel from the transmitter, using endpoint adjustment.

No, I need a possibility in the copter parameter settings. I have not this option at my RC. I cannot adjust the channels 6 and 7 in my RC.

Has someone an idea, to change it in the copter settings? Or is there a possibility to manipulate the pwm signal between RC receiver and copter controller?