Sorry you haven't had an answer yet. I wonder if you've tried googling something like "Rockwood A104" if that would yield anything? The only thing I can make out of the model number is that the basic box of the unit is 10 feet long, just as the 122's, 124's, 128's, etc., all have 12 foot boxes. Good luck!
[later]...I tried following my advice but got nothing from the Google expedition. You probably already tried that anyway. Maybe the 104s aren't out yet. I'm pretty sure I got something when I googled the 102s several months back. (http://www.fairfieldrv.com/detail.cf...2%20Premier%20
) Maybe there's a dealer someplace who has one of those?