convert to sheet metal - feed hopper.

Hi,

I am having trouble converting this feed hopper cone into 12 separate part segments. I want to rip the along the top flange. does anyone know of a cleaver way of doing this?

I have tried a not so cleaver method of using a surface trim to cut out my segments individually but when i go to convert to sheet metal it wont except the top flange bend. I would love to know how some of the more experience users would tackle a part part like. Any input will be much appreciated    

Thanks,

Will

SolidworksSheet Metal