Changing GNOME "default" directories

[Alessandro Boggiano]

Hello all,
how can I change the position of the "default" directories in GNOME ?
For example, I'd like to change Download directory from
 "$HOME/Download" to "/Data/Download".

I changed the line  XDG_DOWNLOAD_DIR="$HOME/Download" in the file
/home/myuser/.config/user-dirs.dirs, logout/login, but no effects.

Where 's the trick ?

Thanks
Alessandro

p.s: Happy 2010 to all! ;)