BSP is already compiled, and you cant load it in the acknex engine.

But since WED bases on a Quake Editor, you can import .map files,
and if you are lucky even apply the WAD Textures.

The light will be probably messed up, and some blocks
for triggers etc need to be removed.
But basically you can import old Quake 1 and 2 maps for example.

Some small recent games of mine:
Griefer 4k http://damocles11.byethost9.com/griefer4k.html
Kobold 4k http://damocles11.byethost9.com/kobold.html
Cave 4k http://damocles11.byethost9.com/cave4k.html