Notes

My company has provided me with a Linksys WAG54GP2 Router/Modem for my ADSL connection.

After requesting iiNet VoIP service to be activate on my line I decided to start configuring my modem. The service was activated in within 2 hours (AWESOME service from iiNet )
I was like a dream.....however my dream came to an end when my modem was not able to get registered by the iiNetPhone services

I read the entire whirlpool forum looking form the right configuration, however this modem have more people with issues that happy ones. Not even iiNet admins have published the setting in the wiki.

Well after 24 hours of fighting the modem settings, I got it up and running. I can receive and make calls without any issue.

Here are all the settings:
Note: Save your settings before changing sub menus otherwise the setting are not applied

Get Firmware 1.0.0.3 and reboot the modem after upgrading

Setup Menu ---> Voice Connection
* Use the same PVC that your ADSL connection (usually PVC 1)

Voice Menu

* Switch to advanced view and then change to Admin Login clicking on both links in the middle of the screen then...
* Set up the primary DNS with iiNet : 203.0.178.191
* User Password: <any password you want>
* Admin Password: <any password you want>
* DNS server Order: Manual, DHCP
=Optional settings=
If you have issues setting up the server, install a SYSLOGDeamon on your PC and put the ip address of your PC in the SYSLOG Server box and Debug Server. Also increase Debug level to 3. This way you will get the output of what's going on with your VoIP connection.
================
Voice Menu --> SIP
* SIP Server Name:sip.<your state>.iiNet.net.au (I.E. sip.nsw.iiNet.net.au)

Voice Menu --> Provisioning
* Provision Enable:NO

Voice Menu --> Line 1
* Line Enable: YES
* NAT Mapping enable:Yes
=Optional= SIP Debug Option:FULL
* Proxy: same as SIP Server setting above
* Register: YES
* Use DNS SRV: YES
* Outbound Proxy: <Clean this field, delete if there is anything>
* Use Outbound proxy: NO
* Use OB Proxy in Dialog: NO
* Make Calls without Reg: NO
* Ans Calls without Reg: YES/NO <your choice :) >
* Proxy Redundancy Method: Based on SRV port
* Display Name: <your VoIP number with area code>
* Auth ID: <your VoIP number with area code>
* Password: <the password provided by the phone team with the activation of the service>
* User ID: <your VoIP number with area code>
* Use Auth ID: YES
* Preferred Codec: G711a (This could vary depends of your connection)

When finish, go back to VOICE --> INFO

It should say Registration State: Registered
If not, restart your modem.

Hope this helps others Linksys users or future ones :-)
This modem is very good. I'm 3Km of the exchange and using ADSL2 settings is connecting better then when I was using ADSL1.
(Other modems run worst in ADSL2 that ADSL if you are far from the exchange like me)