Asterisk configuration problems helphelphelp


I am a new user of Asterisk and have successfully it up on a pc, i have been trying to use sip phone lite which i down loaded and setup again that was fine, but i cannot get sipphone lite to connect to the Asterisk box, i added the following extension to test the Asterisk box:-

Phone protocol: SIP rfc2833
extension number: 200
extension password: 1234
full name:
voicemail password: 1234

And on the Sipphone lite i set up the following under the System Settings>>>Sip Proxy>>>Default :-

Enabled: yes
Display name:
Username: 200
Authorization User:200
Password: 1234
Domain/Realm: (Asterisk Box IP)
Sip Proxy: ( Asterisk Box IP)
Out bound Proxy: (Asterisk Box IP)
Use Outbound Proxy: Always
Send Internal IP: Default
Register: Always
Voicemail:SIP URL

Under the Network menu i have set the following:-

Listen SIP Port: 5060
Listen RTP Port: 8000

Out Bound SIP Proxy: (Asterisk Box IP)

Nothing else has been set, so my SIPPHONE SHOULD NOW SAY Ready to dial, BUT instead when attempting to login it says login timeout

Now i can see the Asterisk box on the internet, i can login to the web interface any where in the world which i recently did from spain, but cannot get sipphone lite to become readyfor use without timing out.