I too was working with SSU. I wasn't even able to install the module manager thats needed to install SSU. I tried to install Model Manager rev 16 because thats the only version working with 1.3.8 (thats the version my site was working on. After the updat to 1.5 all my installed mods stopped working. I also would like my sitemap creater to work...

I read this thread

http://www.zen-cart.com/forum/showthread.php?t=183643

keeping that thread up to date is verry important

and it has only a few mods working unfortunaly ssu is not one of them so far maybe the yellow person who made it can make the adjustments ?

I was made to upgrade to 1.5 by my hostingcompany