How to make textured transparency work ?

Material properties should be:
"00 02 01 00" (MatClass properties, top to bottom), and some texture with alpha channel must be used. Where white on alpha will be non-transparent, black - transparent, shades of grey - semi-transparent (lighter - less, darker - more transparent).

And now bugs:
For example you`re trying to make front light glass:
And you got glitch - reflectors are rendered ontop of the glass, where they should be behind it !
Cos of limitations of WR engine, transparent surfaces (textured) can`t use Z-buffer.
Here is solution: 
When modeling - make glass polygons to be last in order of creation (in Lightwave it`s achievable by cutting & pasting of required polys, this way they are placed last). This way you`ll "emulate" Z-buffer :)
Now WR will draw scene correctly.

For Example you made half-transparent brakelights, and when you turn car, you can see wheels ontop of brakelights. (It`s common problem even with original WR cars).
Why: May be wheels draws later than car body.
Solution: Place some not transparent polygons right behind brakelight. This way they will draw ontop of wheels and brakelights ontop of em both :)