I am having trouble just ripping 3 edges and convert this part into sheetmetal. Anybody have idea?
Try the Insert Bends command:
You don't need to Rip any edges. Just select the Fixed Face and 3 Bend Edges, and the last edge will be automatically selected as Ripped.
Here's another method starting as a Sheet Metal part instead of converting a solid.
Please post a sample picture, because I'm using 2010 version.
Sorry, I missed the "Older Version" message.
Anyway, I don't know that it will help, but here they are;
Retrieving data ...