Mod gone wrong! Need a button for X-Session Pro

So I was modding my X-Session Pro and I lost one of my tactile buttons--it's the fatter one that the arrow is pointing to below. I have searched high and low for this thing... No clue what happened.



I was wondering if anybody has one laying around or would care to part with one for cheap or nothing. I'll pay for any shipping expenses. I am located in the US.

I am painting the buttons so it doesn't matter which one you care to donate. If you care to help please PM me. I figure it's a long shot but I'd check here before I just dropped $40 on another XSP. Thanks!