I don't really think it's possible because the case that goes inside the silicone is very tight and can only fit the phone itself with, normal battery
There is a small square like box inside the case, it's probably no thicker than a 1/3 of an inch long so maybe if you can cut that out, then maybe you could get the case to close with the extended battery in it, but idk
I used to use physical buttons, and then I found button savior
-S. T. C
Sent from my rooted, debloated CM10 jelly bean 4.1.2 Samsung Galaxy S3 #LikeABo$$