How can I determine if a DsCpushButton object is sensitive or insensitive?

I tried:
ret = get.object(conf.button,DsNsetState,value1)

But with that code a BW-message with:
resource DsnSetState for object 174 of type DsCpushButton in process 12 not allowed

comes up!!??

I just found in the documentation: The "DsNsetState" is not readible.
But isn't there any other function to determine if a button is sensitive or not?