[CentOS] Help with pppd

Hi guys

I'm new to the list. There is something I want to ask.
I'm running Centos 5.3. Everything works pretty good.
I need to set up somescripts to make a dialup conection to a closed network.
I'm using the scripts from ppp-2.4.4. Everything id going fine exept
for one issue.
Remote access server use radius autentication.

How can I dial in using ppp-on script and auteticate against the
remote radius server?

Hope some of you can help. Thanksin advance.

David