Can i use Mecanim IK with scaled bones?

Hi guys,

I want to scale parts of an avatar and use IK at the same time.

However when i scale for example the arms, the arms will not use the IK target anymore but a nonexistent scaled version of it. in the attached image, the green area is the shoulder while the red area is where my IK target object is. (the black thing is supposed to be an arm)

i read this is because the way mecanim uses the skeleton to do IK calculations before applying scaling, so i guess my question is can i maybe recalculate the skeleton somehow?

i know there are third party solutions like FinalIK that can do this but my question is specifically if this can be done using the mecanim system somehow.