Command Line Turn Processing under Steam?

Hi!
Please excuse my huge n00bness.

I'm running SEV 1.74 under Steam and WinVista. I want to play a Manual File Transfer game
with a friend, but have had problems trying to process a new turn after collecting all the .plr files.

In the manual, they say you can process turns for such games by doing it on the commandline.

I've tried to run the SE5.exe file directly, and it fails, complaining about not having the steam.dll.
Trying to run the standard Steam Launcher (with the necessary command line arguments tacked on the end) is just as fruitless.

Tried to make a batchfile for it too... nada.

So, I am after some hints and tips on how people have managed to host games via Steam/Vista.
I am pretty sure there would be at least some people out there who know how.

Regards,
Nile.