Sony Ericsson :: S312 - Middle Button Snapped Off / How To Fix?

Although I got my S312 a week ago it feels really nice in hand and really expensive but still like plastic, I do own a Elm, X10. The Elm was just given new to me from Vodafone, so yeah and the X10 is my general phone, but I need my S312 as it is my spare phone or a phone that I use at times when the X10 is ruined (hopefully never) or I am going somewhere where I would never dare bring my X10.

Its my spare phone and no being able to click ok / middle / select is annoying theres no point keeping the phone, so how to I place the middle button back on, I tried semi-super glue (like the ones you get in model sets) and that didn't work (just made it smell ) and I tried double sided tape, it worked but it fell off because the tape is slightly bigger and because it increased the hight about 1cm then it should be so when I click it it will fall off. How do I fix it, here are some shots.