You can configure te program to pretend that buttons or axis on your controller do something else. So you could assign your x-axis, which should be left/right on the wheel to pretend they are mouse x-axis.
The program is for gamepads, so you can control the mouse cursor with your control-stick. As you control the mouse cursor directly, you can use the gamepad in any game that uses a mouse cursor (read: every modern shooter, strategy game, etc.).
You can also assign gamepad buttons to pretend they were keyboard buttons, so you can set your gamepad's "x" to you your keyboards "r" so you can reload your weapon with the x-button on your gamepad in games that normally don't support gamepads.
In this case though, the program won't help you, because the left-right steering of a tank is controlled with keyboard buttons, not axis. That means, that as soon as you turn your wheel far enough so it exits the dead-zone, it counts as a button press. You can steer fluidly then.
However character movement in UT2004 and RO allows the use of axis although its not officially supported. For that you have to edit the RedOrchestra.ini file as I posted it in the linked thread.
It worked fine with my gamepad but I can't remember if it also allowed fluid turing in he tanks. You have to ry that but I guess it should work.
Good luck.
EDIT: Oh, and its not my program. I'm neither the writer, nor the owner of that thing. I just stumbled over it some time ago and it was useful for me so I posted it here. As I said though, it won't help in this case.