I want to use freeradius to manage my socks5 proxy

I configured a socks5 proxy. This question for me is how to authenticate users who I permit to use my socks5 proxy and account them--such as period and data flow--- I do not know how to integrate socks5 authentication and freeradius together. Is there any one have any idea or can provide me some docs. to help me. Thank you very much -- please visit my blog http://blog.csdn.net/taft