Yes, I'm using it. The locale is not fully taken over, languages are, but the format is currently not. There are some different patches in the jira, but at least mine seems to have some problems (after a validation error the format is lost). Besides that, I think it is less usable for dates far in the past (but not as unusable as the icefaces one is, that is even less usable)
The background transparancy could be becuse you do not have the background image in the right place (look at the css)
Yes, you need to style date picker. Look at its usage in the booking app or in seampay for example css.
I am working on integrating the locale submissions, and it will be in Seam 1.1.5.
I ran into the same problem. I copied all the Date related style from screen.css and all the images over to my probject, but it stll shows up as transparent. I wonder what files I need to make it work. Thanks!
Look at date.css in the booking app.