Homeworld 2 Multiplayer patch

[Cosmic99]

Hi,

First off I'm not looking for any cd-keys here.
I have my own copy of HW2 but my brother and I can't play online together on 2 seperate computers on our lan (and we dont want to buy 2 copies). Im looking for a method to either modify my existing key or patch the game so it doesnt look for the key when it goes online or something. I have found my cd-key in my regestry but I don't know what to do with it.

Thanks for any help in advance, cheers.