I also step in this trap..
Looking on the US forum, there is loads of topic on just this...
While replacing the shocks, I snapped 1 of the bolts, even though I soaked it for about a week... I tried but could not drill it out as there was still a little bit still sticking out, and the drill keeps on slipping off..
In the end, I lift the body a bit and use a chisel to break the nut off (as these are just spot welded on) then replace it with a nut and bolt .. have to say, not the easiest to get it back on - but it worked in the end..