Emacs VC vs Google-Code SVN

[bebop52]

I used Google-Code (with Subversion) for hosting a Latex-Project from
a Windows XP machine with a TortoiseSVN Client. Now I changed to
Ubuntu Lucid and checked out the project on my new machine with the
newly installed svn-client.
But I cannot commit my changes (from emacs), because the username and
the password for Google-Code is not set:

I discovered the server and config files in /etc/subversion and in my
home directory. But honestly, I don't understand how and where to set
password and username in an easy way. I spent (too) much time, so I
would appreciate some help.
I would like to do C-x vv on my Latex-file and nothing else ...