Programmatically set the MinValue of a EVEIntPopupSliderComboBoxWidget

I use a EVEIntPopupSliderComboBoxWidget in my InDesign C++ plug-in and want to programmatically set the MinValue and MaxValue in the dialog controller.

fr file:

EVEIntPopupSliderComboBoxWidget // Opacity percentage slider
(
	kPollingSliderWidgetID, // The Identifier for this Widget
	kSysSliderPMRsrcId, // kPMRsrcID_None, 
	kBindNone,              // Frame binding
	Frame(0,0,60,25)        // Frame(l,t,r,b)
	kTrue,                  // Is this visible
	kTrue,                  // Is this enabled
	0,                      // The WidgetID for the nudge button
	1,                      // small nudge amount
	10,                     // large nudge amount
	3,                      // The maximum number of characters
	kFalse,                 // integer readOnly value
	kFalse,                 // Notify on key stroke
	kTrue,                  // Enable range checking
	kFalse,                 // Allow blank entry
	300,                    // The upper limit
	5,                      // The lower limit
	"100",                  // The String value
	100,                    // slider length in pixel

	kEVERegularSpaceAfter,
),

In Controller::InitializeDialogFields:

IControlView* controlView = panelControlData->FindWidget(kPollingSliderWidgetID);
InterfacePtr<ISliderControlData> sliderControl(controlView, UseDefaultIID());

sliderControl->SetValue(config->getPollInterval());
sliderControl->SetMinValue(Configuration::MIN_POLLING_INTERVAL, kFalse, kFalse);
sliderControl->SetMaxValue(Configuration::MAX_POLLING_INTERVAL, kFalse, kFalse);

It does not work, the min and max values remain the same as specified in the *.fr file.

Setting the SetTextValue works fine, thought.

this->SetTextValue(kPollingSliderWidgetID, config->getPollInterval());

Retrieving the value later works too:

IControlView* controlView = panelControlData->FindWidget(kPollingSliderWidgetID);
InterfacePtr<ISliderControlData> sliderControl(controlView, UseDefaultIID());
PMReal val = sliderControl->GetValue();
config->setPollInterval(ToUInt32(val));

Can you tell me what i am doing wrong?

Best regards