90 zr1 front arm bolt how to remove?

[italian job]

Hi all, I'm going to replace my old front arm bushings these days. I have all ready to pull out the lower arm, but the rear bolt is stopped by a car's frame item, that is bolted to the main frame (it seem to be a frame reinforcement as found on z51 and z52 packages) and where engine mounts are bolted too. So I can't pull out the bolt unless I remove the frame item too...
This sound bad to me, maybe there is another way?
Any suggestion?
I know my english language is not too good, so please take a look to my pic for well understand my problem.
Pic is taken from under the car.

Thanks all.