I think you've to do some formatting in your data source first. Tableau can not recognise your abbreviated region names like ASIAPAC or V.E. I would suggest try to add a field called Country. And in list all the countries for respective regions. Then connect to tableau. Using filled map put country field on details and region on color.
Let me know If you've any query.
Sorry I din't get you. Could you please elaborate more on this.