It is possible to have a key switch with stay put positions at 0° and 90° and a spring return between 180° and 90° via the configuration software ?

No, it isn't possible to have a spring return at 180°, in your case the solution is to have a spring return between 120° and 90°.

It is why you don't find the possibility you want in the configuration software.

Released for: Schneider Electric India