How to set Monitoring Discovery Interval for Group Population(GroupPopulator) in SCOM

Hi,

Here with I have created discovery with SystemCenter.GroupPopulator.

<Monitoring>
    <Discoveries>
      <Discovery ID="mydiscovery" Enabled="true" Target="myclass1" ConfirmDelivery="false" Remotable="true" Priority="Normal">
        <Category>Discovery</Category>
        <DiscoveryTypes />
        <DataSource ID="DS" TypeID="SystemCenter!Microsoft.SystemCenter.GroupPopulator">
          <RuleId>$MPElement$</RuleId>
          <GroupInstanceId>$Target/Id$</GroupInstanceId>
          <MembershipRules>
            <MembershipRule>
              <MonitoringClass>$MPElement[Name="SC_a6e117fa996b47c4ae886c188bd8b2ae_Service_b3ad7ca40a1849158c3111d9d508e724"]$</MonitoringClass>
              <RelationshipClass>$MPElement[Name="SCMembership_ecd4ff08a512499d8cbc61f024d165f2"]$</RelationshipClass>
            </MembershipRule>
            <MembershipRule>
              <MonitoringClass>$MPElement[Name="SC_bd2b10979bb54fcf8392edf4eda0b0e1_Service_b3ad7ca40a1849158c3111d9d508e724"]$</MonitoringClass>
              <RelationshipClass>$MPElement[Name="SCMembership_c30716b6e57140ac96fcd406a7bce0cb"]$</RelationshipClass>
            </MembershipRule>
          </MembershipRules>
        </DataSource>
      </Discovery>

</Discoveries>

</Monitoring>

i referred below link, 

http://social.technet.microsoft.com/Forums/systemcenter/en-US/291585a6-d7e3-4c58-a703-dc0879ab2bb9/scom-discovery-interval-configuration?forum=operationsmanagergeneral

How to set  Interval for this above discovery?

Thanks

-satheesh