uac: extend docs for default_socket with a note about tcp_reuse_port

src/modules/uac/doc/uac_admin.xml

@@ -567,16 +567,18 @@ modparam("uac", "reg_gc_interval", 60)
 		<para>
 			Default socket to be used for generating registration requests and sending
 			requests with the function uac_req_send(). Useful e.g. when several public
-			interfaces are available.
+			interfaces are available. A send socket in the $uac_reg variable used
+			together with the uac_req_send() function will override this parameter.
 		</para>
 		<para>
 		<emphasis>
 			By default no default socket is defined, the send socket is choosen from the
-			<emphasis>tm</emphasis> module when the requests is send out. A send socket
-			in the $uac_reg variable used together with the uac_req_send() function will
-			override this parameter.
+			<quote>tm</quote> module when the requests is send out.
 		</emphasis>
 		</para>
+		<para>If you want to force a certain TCP port (e.g. 5060), you will need to set
+			the <emphasis>tcp_reuse_port=yes</emphasis> core parameter as well.
+		</para>
 		<example>
 		<title>Set the <quote>default_socket</quote> parameter</title>
  <programlisting format="linespecific">