Update:
Unfortunately the USA remote fobs do not work for the WG, they transmit at 315 MHz, the 2004 Australian models use 434 MHz.
You can tell by reading the top number on the SMD oscillator. That is the chip looking device nearest to the battery.
I can confirm the boot release has no function on the Australian delivery WG.
Our Fobs did not have the panic button exposed, but do have the full complement of 4 buttons on the PCB. I have adapted the USA supplied 3 button fobs to add the panic function to mine.