Some banks will facilitate the carrying over of negative equity into a new purchase as long as you qualify for the new mortgage. Which bank(s) are you with?
PaddyW's right - you can't access your pension funds before retirement, which for many schemes is no earlier than age 50 except in a case of serious ill-health.
There is a scheme starting soon (assuming it passes into law) whereby one can access AVCs from a pension scheme early, but it's limited in its availability and even more limited in its appeal. I wrote a piece in yesterday's Sunday Business Post about it. You can read that piece [broken link removed].