WeakAura - Percent Health Bar for active battle pets

[Flohsakk]

Some abilities of battle pets are based on Health-Percent, so I already did 2 text displays to show this for my and the opponent's active pet in a pet battle. I would like to add two progress bars based on percent but I don't know how to get that into weakauras because I don't find something for active battle pets to put into the specific unit field like "boss1" or the like. Are there unit IDs for that or ist there a custom function and where do I have to put that (trigger oder display)? Thanks for help!