Hi guys, the small oval shaped skull-cap pad in the base of my Arai helmet has fallen out as the foam backing on it started to rot. Unfortunately its not a removable/replaceable lining model. The helmet and rest of the padding is in good nick, so I';ve just sewn a new piece of foam backing onto the oval piece ready to glue back in, but not sure what to use. I've no idea what type of glue was originally used to secure this bit. I was originally going to use super glue, but seem to remember reading somewhere that it eats/melts white styrofoam (the bare impact foam it will be glued to) so am reluctant to use it. Any suggestions??