A break will do it, or making the bend on a table, aligning the 'line' a tad off the table to allow for the bend radius.
You should anneal it, if 5052 alloy the anneal temp is 650-degrees. You can use a Temp-Stik or some say put Sharpie Marker around the line and when the marker burns away, you hit the 650. The melt temp is 1100, so you have some range here. I'd recommend MAPP gas waved to heat uniformly and fast.
If no brake, I'd make a wood frame to pull down on the piece to be bent in one shot. Go past, or further bent, than where you need to go, by a good inch I'd say, due to springback and memory. It would be easier to relax the bend, then deepen it (to me). Definitely re-anneal, as 5052 work hardens.
PM if you need more assistance ...