Core support rust - fixable???

[BossHogg69]

I did a quick search but couldn't find much in regard to fixing rust on a core support, namely the area under the battery, which is where my problem is. I don't want to buy an aftermarket one, because from what I've found and read here, they don't fit well. The pics below are what I'm dealing with. Other than the pics, everything else is solid, its just the area under the battery tray that has issues. Any ideas on fixing this? The threaded bolt holes are still there, but the flat area around them is pretty thin, and the lip around the edges is about gone. I have a welder handy and don't mind taking on this challenge, just wanted to check and see if anyone has done this type of repair before and how it turned out. Thanks in advance for any help and/or advice!