Rig > Animation Type > Humanoid

I am using foot IK for animations.
When i try to configure the avatar definition (“create from this model”) i cannot use the ankle or feet because they are not children of the shin bone. This is obvious because I am using IK and therefore they cannot be connected or else it would not work as IK is intended.

Does humanoid animation type only support forward kinematics? How am I supposed to use Humanoid animation type to create an avatar with IK?

I’m so confused. Can anyone please help?

Thankyou

bump