Simply add to your client.cfg the following line :
Application = { "ryzom_dev", "./client_ryzom_r.exe", "./" };
Currently you can't log in directly out of game, which is really bad if you want to use ARK/ARCC :( a workaround is adding a new app, where the url point to
http://manda.glorf.fr/arcc/access_outgame.php
Then go to the app, it will print you the URL you'll need to use. Yhe string is written to [[1]], so you don't have to manually paste it. After that, go to the URL, it'll ask for your password, and you are logged!
Password: mozyr
Password: ryzom