Send DTMF with SIP INFO (c2600) configuration question

Question

I have a cisco 2600 with VIC-2FXS port as VOIP Gateway, connecting to SIP Server to receive SIP Incoming calls. I am able to receive call and the vocie has been pass through both way; and I would like the 2600 send DTMF as SIP info but was not able to do so. I have ios 12.3, and from this configuration guide http://www.cisco.com/en/US/docs/ios/12_3/sip/configuration/guide/chapter8.html#wp1048824 , it does not require any config for SIP info. I must missing something here, please advice. Thanks.
The config is following -
version 12.3
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
hostname abc
boot-start-marker
boot-end-marker
enable secret 5 xx
enable password xx
memory-size iomem 10
no aaa new-model
ip subnet-zero
no ip routing
no ip cef
interface Ethernet0/0
ip address 192.168.1.15 255.255.255.0
no ip route-cache
full-duplex
no ip http server
ip classless
voice-port 1/0/0
voice-port 1/0/1
voice-port 1/1/0
voice-port 1/1/1
dial-peer voice 1 pots
destination-pattern 1000
port 1/1/0
dial-peer voice 2 pots
destination-pattern 1001
port 1/1/1
dial-peer voice 10 voip
destination-pattern 1.T
session protocol sipv2
session target ipv4:192.168.1.224:5061
session transport udp
codec g711ulaw
dial-peer voice 3 pots
destination-pattern 1100
port 1/0/0
dial-peer voice 4 pots
destination-pattern 1101
port 1/0/1
line con 0
line aux 0
line vty 0 4
login
end

Answer 1

I tried to set it, and for IOS 12.3(26) - the latest for 2610 - which dose not have that option. I use dtmf-relay rtp-nte instead; but it did not send RFC2833 event. From ethereal, no OOB events. It seems that the config I have does not have OOB DTMF enable; I compare the config I have with other examples but can not found anything wrong. Any suggestion, and what debug message I should enable, that may help to identify the issue.
Thanks.
voice class codec 1
codec preference 1 g729r8
codec preference 2 g711ulaw
interface Ethernet0/0
ip address 192.168.1.15 255.255.255.0
full-duplex
voice-port 1/0/0
voice-port 1/0/1
voice-port 1/1/0
voice-port 1/1/1
dial-peer voice 1 pots
destination-pattern 1000
port 1/1/0
dial-peer voice 2 pots
destination-pattern 1001
port 1/1/1
dial-peer voice 10 voip
description Outbound Calls
destination-pattern 1.T
voice-class codec 1
session protocol sipv2
session target ipv4:192.168.1.250
session transport udp
dtmf-relay rtp-nte
no vad
dial-peer voice 3 pots
destination-pattern 1100
port 1/0/0
dial-peer voice 4 pots
destination-pattern 1101
port 1/0/1
dial-peer voice 100 pots
destination-pattern 8...
port 1/1/0
forward-digits 3
dial-peer voice 20 voip
description Incoming calls from PBX
incoming called-number .T
voice-class codec 1
session protocol sipv2
session target ipv4:192.168.1.250
dtmf-relay rtp-nte
no vad