how to change the userfullname ?

[David Ansart <ansartd@yahoo.fr>]

Hi

I can't change the userfullname of my own user. The problem is that it 
contains a space.
I want replace "Debian Live user" by "Network User"

in --bootappend-live, with the option userfullname, i tried without 
success "Network User", \"Network User\", \\\"Network User\\\", Network\ 
User....

Could you help me ?

Thanks