@Feindbild: As a matter of fact, I do use WED for all my levels and even to create some objects, like shelfs, crates or vents etc.
Altough, i think when im done with a Level I will convert all in models for speedresons. I simply export the levels/models via WED to a .mdl-file.

You need alot practice for WED. I started with WED (Gamestudio in gerneral) back in A5-times