How to attach body padding?

So, I've begun construction on my next project Guilmon! Anyway, I want to add some padding to the thighs and calves to beef up the legs to look more accurate. He's plantigrade, so what I've done before won't work the same way. SO, I was wondering HOW people fasten the foam to the inner "body" suit? Do you just use hot glue? I'd assume that'd be really uncomfortable as I can't even handle glue residue on a pair of sock paws I attempted, let along rubbing on my legs. x.x I figure I'll probably have to get a diveskin for this suit which brings me to another issue. I was hoping to go for a back zipper, since Guilmon has a padded tum. But the diveskins I've seen all have a zipper on the front, so I'm not really sure how to handle that. I've considered making the belly separate and using the black stripes that go from his neck and back to attach the belly, but I don't really want to go that route in fear of how it would look. T.T

Making plush padding was another thought, but not sure how to go about that either. x.x

Suggestions? Here is the concept art I've made for it.