[Serusers] SER + RTPProxy don't seem to work together??

[szj]

Hi,

My testing environment is as follows.
SER+RTPProxy's ip: 111.122.133.100
NAT device's ip:   111.122.133.4
SIP UA A's IP:  192.168.0.62:9000
SIP UA B's IP:   111.122.133.100:5000
If I use the SiP UA A to call UA B outside the
NAT clouds, I think the SER should communicate
with RTPProxy and modify the INVITE message's
SDP message's media IP and Port. But I checked
the UA B's log and found that the ser only changed
the SDP''s IP, not the media port.
Here is the UA B's log:

INVITE sip:861111 at 111.122.133.100:5000 SIP/2.0^M
Record-Route: <sip:111.122.133.100;ftag=1509219066;lr>^M
Via: SIP/2.0/UDP 111.122.133.100;branch=z9hG4bKb6f1.9cf45a65.0^M
Via: SIP/2.0/UDP
192.168.0.62:9000;rport=12072;received=111.122.133.4;branch=z9hG4bK1145650245^M 


From: <sip:862222 at sip.suntest.com>;tag=1509219066^M
To: <sip:861111 at sip.suntest.com>^M
Call-ID: 638544678 at 192.168.0.62^M
CSeq: 20 INVITE^M
Contact: <sip:862222 at 111.122.133.4:12072>^M
Max-Forwards:  ^M
User-Agent: User Agent0.1^M
Subject: This is my first SIP call^M
Expires: 120^M
P-Info: VQem2WySucv0oaiOqT7HAmtlPhMYPd3Kn58o4xX9o5tL^M
P-Need-Security: Yes^M
Require: P-Need-Security^M
Allow: INVITE, ACK, CANCEL, BYE, OPTIONS, REFER, SUBSCRIBE, NOTIFY,
MESSAGE^M
Content-Type: application/sdp^M
P-Security-Nobody: abnPtllQ4gF5deL2u5UfUnfzUcJhomFI+yj1mYR374s=^M
Content-Length: 310^M
P-hint: usrloc applied^M
^M
v=0^M
o=nobody 20041028 20000001 IN IP4 192.168.0.62^M
s=A call^M
c=IN IP4 111.122.133.4^M
t=1112000912 1112004512^M
m=audio 9500 RTP/AVP 0 8^M
a=rtpmap:0 PCMU/8000^M
a=rtpmap:8 PCMA/8000^M
m=video 10000 RTP/AVP 98 31^M
a=rtpmap:98 H263/90000^M
a=rtpmap:31 vf=4/CIF/1/768^M
a=direction:active^M
a=oldmediaip:192.168.0.62^M
the UA A's original audio port is 9500, you see
it is unmodified through the SER.

Next is the part of my SER.cfg config:

if(method == "INVITE")
{
   fix_nated_sdp("3");
};
I thinks the SER should relaced the SDP media IP and port
with the return valued by RTPProxy. That is, media ip is not
the NAT device's IP, but RTPProxy's IP, 111.122.133.100, and
the audio port is the port returned by RTPProxy. Now I can't
see the modification of the media port by RTPPProxy.

Am I right??

Thanks for your help!
Best Regards.

Sun Zongjun