Modifiy parameters of derived part feature

Hello

I have a part with many parts inserted in. I want to uncheck Custom properties in all the parts.

In the API help there is an exemple for modifying some options (planes, sketches) but i can't find something about custom properties. In this section :

IDerivedPartFeatureData Interface Membersthere nothing about properties

Is it possible to do what I want or not ?

Thank you

SolidworksApi macros