Set background color for QwtDialSimpleNeedle

I see how I can set mid and base color for QwtDialSimpleNeedle as input parameters to the constructor.
But from the documentation I don't find a way to specify the color for the background of the needle (I mean the rectangle thta contains the needle).

Can someone give me a suggestion, please?

If you mean the thing in the center: it is colored using QPalette::Base. But Qwt is open source - you can simply check the code in qwt_dial_needle.cpp/qwt_dial.cpp to see what is going on.

Uwe