It's hard to say, it sounds like
your config is correct. Here is
an example of one working config:
user Password = "cisco",
Service-Type = Framed,
Framed-Protocol = PPP,
Framed-IP-Address = x.x.x.x,
cisco-avpair
= "lcp:callback-dialstring=xxxxxxxx"
cisco-avpair
= "lcp:nocallback-verify=1"
You might have a look at "debug aaa
authent" and "debug aaa author" to
see if that helps identify the problem.
You might also ensure that you are
using recent code.