how to flatten a part using sheetmetal

Hi all,

I have made this clamp, I will add holes on the ends later, but for now my problem is that I cannot flatten it. I have tried converting it to a sheet metal part and also adding bends.

What I am looking to do is to flatten it to get the total length of material I will need a before it is bent.

The drawing was made with SW2011.

SolidworksParts And Features