Flatten part without planer face?

Hello,

I am trying to create a pattern for a ruff that I would like to fabricate out of sheet metal.  I've created a solid body that represents the final product but I am struggling to find a way to flatten it.  It seems the problem is that there is no planer face to select.  I'm wondering if I'm missing something or if there is any trick I can use to end up with the same result. 

Thanks,

Eric

SolidworksSheet Metal