How to get idMso Ribbonname of a selected meeting in outlook calendar?

Question

how can i reference this ribbon (idMso) to display my custom add in group there? The ribbon is only visible when I select an appointment item. I want to get the item from the selection with my add in. But I don't know the idMso of this ribbon. It is not TabMeeting or TabCalender.

    <?xml version="1.0" encoding="UTF-8"?>
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui" onLoad="Ribbon_Load">
  <ribbon startFromScratch="0">
    <tabs>
      <!--<tab idMso="TabAddIns" insertBeforeMso="TabMail">-->
      <tab idMso="TabMeeting">
        <group id="GetTermine"
               label="SITBS">
           <toggleButton id="OnActionCallback" label="Get Termine" size="large" onAction="OnActionCallback" />
        </group>
      </tab>
        <tab idMso="TabAppointment">
            <group id="GetTermine1"
   label="SITBS">
                <toggleButton id="OnActionCallback1" label="Get Termine" size="large" onAction="OnActionCallback" />
            </group>
        </tab>
    </tabs>
  </ribbon>
</customUI>

6SvwQ.png Greetings