I tried to configure version 1.5beta since I was curious about the changes made in this version. Since others are probably interested in this version, too, I would like to write about some things and particularly my failure to achieve the goal. Hopefully, this will save you trouble and time
The setup is different from the prior versions. Extracting textures works like usual. The main problem are the entities. I wasn't able to include WQ entites in Radiant. More precisely, some showed up while others did not. Probably, the some entity definitions are screwed and 1.5 is more fussy about this than 1.4. Or 1.5 loads them in a different order. There are some xml-config files where new "games" can be specified (including shaderlists, entities, etc.). Messing around with these didn't help either. 1.5 is supposed to load custom entites automatically if the game/mod is properly specified. However, it doesn't recognize WQ as a "game". ATM version 1.5 does not come with plugins (no brush cleanup, no gtkgensurf, no nothing). Additionally, you should be prepared to press "CTRL + S" quickly and often. It stands for "Stability"
The botton line is this: if you're as new to mapping as I am go for the 1.4 version. If you're much smarter than me or really like to configure stuff, go ahead and let us know ...
I didn't bother to search the net for tutorials and other help, so there may be simple solutions I am not aware of. However, 1.4 does the job. You won't miss the "Create my WQ map NOW!"-button or some other fancy stuff.