Thinking about it, I would not recreate the button system from our WoD files if I were doing them from scratch today - I'd use a user-sortable table to define the priorities and allow the user to control their relative order, the way Shadowrun does.
That just needs a fixed table with allowuserorder="yes", and make sure the component="" of that table is set to a component that has a orderfield="priOrder". Then, a component script on that component will look up the orderfield and convert that into the number of points. And like my previous suggestion, in the editor, you'd set default order values for each of the three picks.
You'll also need a showsortset="" on the table, that uses the orderfield on that component:
Code:
<!-- The priorities table is a user-ordered table -->
<sortset
id="PriorTable"
name="User-Assigned Priority Order">
<sortkey isfield="yes" id="priOrder" isascend="yes"/>
</sortset>