How do I flatten (create Flat-Pattern) a part that has a slot in the bend?

My job requires that I take customer 3D models of parts, intended to be sheet metal, but usually not yet actual Sheet Metal parts in SolidWorks, and create a Flat Pattern that I can save as a DXF file. Normally, I will simply us Insert/Sheet Metal/Bends, and then insert the Flat Pattern into a drawing which I SAVE AS a DXF file.

However, if the part has a slot or other feature (hole, or other cut) that crosses a Bend Line into the area of the bend, when I use that command sequence SolidWorks says "No Bends Found".  If I do Insert/Sheet Metal/Convert to Sheet Metal instead, it may create a Sheet Metal part that will flatten (often with errors), but also sections of the model, usually flat surface adjoining the bend, actually disappear!

The only work-around I have found is to use this incomplete flat pattern and correct the Geometry in the 2D drawing by measuring the 3D model.

Am I missing something? Why won't SolidWorks reliably create a correct Flat Pattern when there is a cut into the Bend? Is there a better work-around?

I have attached a simple model that illustrates what I am talking about. Try to create a Sheet Metal part and flatten it.

SolidworksSheet Metal