Hide some Enum Elements for Unbound control in form ( Combo box)

// Class Declaration of Form

public class FormRun extends ObjectRun
{
    SysFormEnumComboBox         sysFormEnumComboBox;
    Set                         enumSet;
}
// Init Method of Form
public void init()
{
    //Code to restrict only some selected Enum elements appear in Lookup
    enumSet= new Set(Types::Enum);
    enumSet.add(DKTaxType::Statebatterytax);
    enumSet.add(DKTaxType::Statetiertax);

    sysFormEnumComboBox  =      sysFormEnumComboBox::newParameters(element,element.controlId(formControlStr(DKMasterItemTaxValues, MasterItemTaxValues_DKTaxType)),enumNum(DKTaxType),enumSet);
// 2nd parameter , should be the control id of the Combo box.  This works only for unbound control. so it should not link to any of the 
     super();
}