Usernames with spaces

I'm a relatively new freeradius user so I am not really an expert with it. I have two users in the racheck table: "admin" and "d6 40 1a 98". Both with passwords "admin198". Doing this: *radtest admin admin198 localhost 0 testing123* ..returns an Access-Accept packet. But doing this: *radtest "d6 40 1a 87" admin198 localhost 0 testing123* ..returns an Access-Reject packet. I wonder why the user with spaces in the username is being rejected. I've read somewhere that I need to specify "nospace_user". Can I edit that in the radiusd.conf? What should the value be: before, after or no? Our installed version is 2.1.0+dfsg-0ubuntu2, running on Ubuntu 8.10. The backend database we used is MySql. Thanks in advance. Joeven Rex L. Dizon