[tac_plus] Possible to get tac_plus to authenticate using pam_radius?

[SiN]

I seen that PAM can be used to authenticate users, but not sure where
to start.  I tried to just set "login = PAM" to see if any errors
would help determine where to get started (looking for missing config
or something of that nature).  But, I get nothing.  Is it possible to
use PAM to authenticate users to my current radius implementation?
The only reason I even need authentication set up on tac_plus is due
to some of our devices not supporting radius at all, for those I will
need to authenticate using tac_plus - other then that everything is
radius and id like to keep it that way if possible.

Mon Nov 12 17:05:56 2007 [3912]: pam_verify testing
Mon Nov 12 17:05:56 2007 [3912]: pam_tacacs received 1 pam_messages
Mon Nov 12 17:05:56 2007 [3912]: Error 10.248.18.17 tty2: PAM_PROMPT_ECHO_OFF
Mon Nov 12 17:05:58 2007 [3912]: Password is incorrect

is all I see in the logs.  and nothing shows up in the radius logs so
I know its not being sent off to radius

How can I get this set up to use the current PAM implementation on the
system already?  Do I need to install something extra?

this is on solaris 10 using tac_plus version F4.0.4.14