horizontal flip

[Bzdero]

I have a mc on a center of scene that i want to flip horizontal in direction where invisible button (that is size of complete scene) takes on release action. The only way, as i could understand, is to set x scale to -100. I did it all. But the only thing that i can't set is- when i press it the right way (first right of that mc, then left- as i made it) it works OK. But when i do it the other way (left then right), it does the opposite. This is because when x scale is put to value -100 it counts it as it is 100 (because the actual value of mc is 100% indeed). I hope you understand it. If you want to help, i will send you the script.
Thanks!

[mgb]

try;

set variable:"scaler" = -100

setProperty("mc",_xscale)=scaler
set variable:"scaler" = - scaler.

~mgb