Running idea with mustang

A while ago I successfully made IDEA run with mustang, but for some reason I can't get it to run anymore.

I've added this to the top of idea.bat:
SET IDEA_JDK=C:\Program Files\Java\JDK1.6.0\

And this to the bottom of idea.properties:
Didea.no.jdk.check=true

But I just keep getting a dialog which says:
The JDK version is 1.6.0-ea. IDEA requires JDK 1.4.2 or higher or JDK 1.5.

Is it still possible to run idea with mustang?

btw. There's supposed to be cleartype anti-aliasing in new mustang b39.