I've attached a sheet metal part that I want to add corner welds to all 4 of the corners on the inside.  The welds are for added strength, but for aesthetic purposes I want the welds to be on the inside of the corners rather than outside.

Can this be done?  I'm finding SW very limited (or at least non-user friendly) in regards to being able to do sheet metal welds.

Also, I need to run SW Sim on the part after the welds are in place.  Will the welds automatically be accounted for when I mesh & run the sim as a shell, or will I have to treat the part as a solid?

Thanks in advance for any help.