(hopefully the right place to post coding questions)

Has anyone had any success adding tick marks to UISliderControls?
My code looks like this:

    scanRateSlider = [[[UISliderControl alloc]
                    initWithFrame: CGRectMake(.......) ]];
    [scanRateSlider setMinValue: 3.0f];
    [scanRateSlider setMaxValue: 30.0f];
    [scanRateSlider setAllowsTickMarkValuesOnly: YES];
    [scanRateSlider setNumberOfTickMarks: 3];
    [scanRateSlider setContinuous: NO];
    [scanRateSlider setShowValue: YES];
    [scanRateSlider addTarget:self action:@selector(handleSlider:)
and all works as I'd hope, except that I can see no tick marks and all possible floating point values may be selected.

Any ideas, or pointers to source code that does work? Thanks,