Glenda is the Argentina version of Scarlett. Hasbro decided to just make her an alias of Scarlett. They believe most fans will relate to her better than Glenda.
In DDP's G.I. Joe #38 she made her only appearance.
http://www.yojoe.com/comics/image/dd38.shtml
http://img242.imageshack.us/img242/8274/comic38tp7.jpg
Another reason why I don't like the DD comics.

I did a simple swap of heads on mine.