DoubleVectorProperty does not support enumeration domain

DoubleVectorProperty does not support enumeration domain. eg :

      <DoubleVectorProperty command="SetDiscreteTimeStepInterval"
                            default_values="0.0"
                            name="DiscreteTimeStepInterval"
                            number_of_elements="1">
        <!--DoubleRangeDomain name="range" min="0.0" max="1.0" /-->
        <EnumerationDomain name="enum">
          <Entry value="0.0" text="source"/>
          <Entry value="0.5" text="half day"/>
          <Entry value="2.0" text="two days"/>
          <Entry value="7.0" text="week"/>
          <Entry value="30.0" text="month"/>
        </EnumerationDomain>

        <Documentation>Time stride that will be applied to your temporal dataset. This value assumes
          that each timestep represents one single day, otherwise the result will cause puzzles.</Documentation>
      </DoubleVectorProperty>

Does not produce any widget, but it could.