Log Auth_Type in apache logs

Hi,

I wanted to log the Auth_Type in the logs. We are using mod_auth_kerb
with failover to basic auth.
In order to findout the kerb auth failures track the no.of basic auth,
I want to log the auth_type to the logs

I have configured it like this.

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i
\" \"Auth_Type[%{Auth_Type}i]\"" combined

10.85.40.143 - sgopalan@CORP.MYDOMAIN.COM [24/Apr/2007:10:07:56 -0700]
"GET /c/portal/css_cached?themeId=channele&colorSchemeId=02 HTTP/1.1"
304 -
10.85.40.143 - - [24/Apr/2007:10:07:56 -0700] "GET /html/js/
everything.js HTTP/1.1" 304 - "https://lxdm14545.corp.mydomain.com/web/
guest/home" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1;
InfoPath.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)" "Auth_Type[-]"


I keep seeing "-" as Auth_Type. If I use a simple PHP page to print
the http header info, I can see the Auth_Type being Negotiate or
Baisc.

I am wondering why apache doesn't print the Auth_Type.

Can I have any http header to be printed there ?

Am I missing something here ?

--Sriram