How to different Scale and Values in Knob

Qwt 5.1.1

I want to have a knob with the legend going from 0 to 11, and have the underlying value range from 0 to 4095 and smooth rotation of the knob with a mouse.

If I setScale(0.0, 11.0, 1) the legend looks correct but the knob rotates in 10 'clicks' (jumps) without allowing setting it to values inbetween. If I try to set the step size smaller, the printed legend goes crazy (it looks like maxScaleTicks in qwt_knob.cpp isn't used anywhere).

Pointers appreciated.

Thanks,
Doug