How do I do an extruded cut in a sheet metal cylinder

I need to make a cylinder that's 40" long and 52" o.d and put a 15degree cut through it as though its been cut with a saw after being rolled. When I do the extruded cut from a generated plane the cylinders rolled part isn't a true "saw" cut. Its more of a slopped cope. So when the part is flattened to be cut and rolled it wouldn't be a true miter.

SolidworksSheet Metal