I have been around and have seen lots of Sheetmetal parts. Some are started with the flat plate and bend lines are added to the flat to make the bends. Not the exact way I was trained but when you learn the software on your own you do what you can.
The other one is that the part is made with extrudes and or surfacing. Then with out the proper training and an experienced mentor it is hard to get those parts to transfer into a sheet metal part. The convert to sheet metal is a cool tool to have and to use but there are times that it fails. In the time it would take me to figure out why that solid can not be converted into sheet metal I can start a new part and remake the model using the Sheetmetal tools in SolidWorks.
Extend the screen to two monitors and put the original component on one screen and model the new part on the other. Start with a single line sketch and pick the base flange to get you first feature then add flanges jogs ect. More elaborate parts you may want to unfold and add a hole pattern and then fold it back from the flat sheet.
Bend tables and K factors.
These become important when trying to get an accurate flat pattern or production. If you do not have a bending machine to manufacture the parts in house I would not worry about trying to send out a flat pattern for any sheet metal parts that I create. I tell our purchasing department and even put a note on the drawing that a 3D solid files is available on request for manufacturing. Then the guys at the sheet metal place can add the specific information from their bend tables and k factors that are needed for their machines to be able to come up with an exact flat pattern.
Why I recommend these procedures? We sent out drawings with the flat pattern and bend information and that is what was used to make the part. Due to manufacturing process the bent part was not the exact shape that we needed and it did not fit. Giving two processes to choose from they went with the easy one and cut and bent the flat pattern as shown on the drawing, instead of verifying that we would get the dimensioned 3d part that we wanted. They supplied what was asked for but not what was needed.
If you work at a sheet metal fabrication location please add to the comments what you would like to see from those of us that send you parts.