HOw to create vehicles , and ships , i don t find the tuto .

Here's a tutorial on setting them up for BF2

Other than that, its just like regular modeling

And here's the collection of XSI FAQ's in case you missed it

I know it's a turret tutorial, but turrets work the same as vehicles (except you don't need the aimer_y and aimer_x nulls unless you have a turret on the vehicle)