Double knee Character (Insect)

Hi guys, I’m working on a double knees model and I was wondering if it was possible to use the Arttool for the set up i’m looking for.

I see the option “Leg Style” -> Standard Biped, but it’s greyed out and I can’t change this.

Do you have any tips for me ? Maybe on how to get this 2 knees set up working through Arttool

Thanks a lot.