Dial up connection using sim900

Hi Friends
I want to connect my raspberry system to connect internet via sim900 gsm modem for that i am using wvdial method to connect internet my wvdial configuration file like follows

[Dialer play]
Modem = /dev/ttyUSB0
Baud = 9600
Init1 = ATH
Init2 = ATE1
Init3 = AT+CGDCONT=1,"IP","internet"
Dial Command = ATD
Phone = *99#
Stupid mode = yes
Username = ""
Password = ""
if i am connecting 3g usb modem using above configuration the output screen like this

pi@raspbmc:~$ --> WvDial: Internet dialer version 1.61
--> Initializing modem.
--> Sending: ATH
ATH
OK
--> Sending: ATE1
ATE1
OK
--> Sending: AT+CGDCONT=1,"IP","internet"
AT+CGDCONT=1,"IP","internet"
OK
--> Modem initialized.
--> Sending: ATDT*99#
--> Waiting for carrier.
ATDT*99#
CONNECT
--> Carrier detected. Starting PPP immediately.
--> Starting pppd at Fri Jun 14 22:35:19 2013
--> Pid of pppd: 3145
--> Using interface ppp0
--> pppd: Ęy
--> pppd: Ęy
--> local IP address 10.133.163.246
--> pppd: Ęy
--> remote IP address 10.64.64.64
--> pppd: Ęy
--> primary DNS address 89.108.202.20
--> pppd: Ęy
--> secondary DNS address 89.108.195.20
--> pppd: Ęy
it was connected to internet but by using the same command for sim900 gsm modem the output screen like this

pi@raspbmc:~$ --> WvDial: Internet dialer version 1.61
--> Initializing modem.
--> Sending: ATH
ATH
OK
--> Sending: ATE1
ATE1
OK
--> Sending: AT+CGDCONT=1,"IP","internet"
AT+CGDCONT=1,"IP","internet"
OK
--> Modem initialized.
--> Sending: ATDT*99#
--> Waiting for carrier.
ATDT*99#
CONNECT
--> Carrier detected. Starting PPP immediately.
--> Starting pppd at Fri Jun 14 22:35:19 2013
--> Pid of pppd: 3145
--> Using interface ppp0
that is it was connect but local IP address, remote ip address,primary DNS address,secondary DNS address not assigned so i am unable browse the internet please help me how to resolve this problem give me the guidance to resolve this problem thanks in advance

Did you check whether the dialer is supported by GSM sim 900?

Thanks for the reply I am not checked whether the dialer is supported by GSM sim 900 anybody knows which dialer working for sim900 to access internet in raspberry pi please give me the guidance