[Zope] in Properties, how to assign values to multiple selection property

I am trying to add a multiple selection property from the ZMI properties tab. Not sure how to set the name and value pair for each option. Only the name part work, when I set the value of the multiple selection property to another lines property or tokens property. I'm trying to get this: <option selected>Name</option> to this: <option value="21" selected>Name</option> TIA