Sherwood Axis BC Question

I was thinking of making a DIY crotch strap for my Sherwood Axis BC.
Since there's no cumberbun, I get a massive amount of riding up. I am a small build, so even with a 7mm farmer john and weight belt, I can't get the BC to snug me around the waist.

So the question is. What is the backplate of the Axis made of. Is it just fabric through and through?
I was thinking of attaching the crotch strap through zip tie between the wing and the backplate. (imagine the zip tie acting as the slot on a metal backplate)
The zip tie will be placed in the lower velcro slot, where the plastic tank plate and wing connect to the soft backplate.

I'll then feed the crotch strap through an incision in the backplate, lower end. (will this cause it to unravel eventually? will neoprene cement around the incision prevent this?)

Alternatively I was going to attach the crotch strap on the outside of the wing using a zip tie but felt that this would compromise the snug fit of the tank and tank strap.

Thoughts?

Also will this void the warranty?

I think I lost my camera.

The backpack on my BC is plastic, and has a loop in it for a 1" crotch strap. Both my BCs and my two backpacks have the same loop. There's a decent chance that yours does too, under all the fabric. My cushiest BC has cotter pins holding the pads to the backpack, see if you have something similar. My inclination is that you'll be able to do this probably with no modification to the BC at all, but at most a 1" slit in the fabric only, which you can seal up with a lighter or adhesive. And yeah, that'd void your warranty.

Ugh, the backpack's sewn in. I'm not sure I'd take a knife to it; it's actually pretty nice for an integrated BC.

Yeah I figured it'd scrap the warranty.
But I'm pretty sure there's no rigid backplate in there it's all plush and fabric as far as I can feel.
I was hoping the Sherwood rep or anyone else might give me some more insight.

Fair enough Guess I should have checked the Forum.