AutoCAD Inventor :: How To Create Sheet Metal Parts With Square Shapes And Bends Them

Let me start by saying that we rarely use sheet metal parts so I'm not real familiar with that interface.  That said, I can create sheet metal parts with square shapes and bends just fine.  However, I'm currently stumped as to the best way to model what should be a pretty simple plate.

We have a large, thin (1/8") square plate to which we want to add 2 opposing diagonal very slight breaks to add stiffness to the plate.  More specifically, we want these diagonal bends to cover the center part of the plate leaving about a 2" flat flange all the way around the plate.