$FreeBSD$

--- modules/auth/doc/auth_user.sgml
+++ modules/auth/doc/auth_user.sgml
@@ -33,7 +33,10 @@
 	    must be loaded before this module):
 	    <itemizedlist>
 		<listitem>
-		    <para><emphasis>sl</emphasis> -- Stateless replies</para>
+		    <para><emphasis>sl</emphasis> -- Stateless replies (if <varname>use_tm</varname> is 0)</para>
+		</listitem>
+		<listitem>
+		    <para><emphasis>tm</emphasis> -- Transaction module (if <varname>use_tm</varname> is 1)</para>
 		</listitem>
 	    </itemizedlist>
 	</para>
@@ -103,6 +106,26 @@
 		<title>rpid_suffix</title>
 		<programlisting format="linespecific">
 modparam("auth", "rpid_suffix", "@1.2.3.4>")
+</programlisting>
+	    </example>
+	</section>
+	<section>
+	    <title><varname>use_tm</varname> (integer)</title>
+	    <para>
+		If set to 1 then the auth will use <function>t_reply()</function> function from
+		the tm module instead of <function>sl_send_reply()</function> function from the
+		sl module for sending replies.  This allows challenge responses to be processes
+		statefully if necessary.  When set to 1 script writer need to ensure that transaction
+		exists when <function>www_challenge()</function> or <function>proxy_challenge()</function>
+		is called, usually by calling <function>t_newtran()</function>.
+	    </para>
+	    <para>
+		Default value is 0.
+	    </para>
+	    <example>
+		<title>use_tm example</title>
+		<programlisting format="linespecific">
+modparam("auth", "use_tm", 1)
 </programlisting>
 	    </example>
 	</section>