auto login with xfce?

[Daniele]

> To make your whole system work properly you should start your xfce4 as
> follows:
>
> su -l user_name -c 'source /etc/profile;startx &' &> /dev/null

Hi every1,
I tried that command out in Ubuntu Gusty at sturtup but it doesn't seem to work.
su - user_name -c startxfce4   doesn't work either.
Is that because in ubuntu I should use 'sudo <something> ' instead ?

thnaks for help,
Daniele