Not possible with common output folder?

Eclipse 3.3.0, JadClipse 3.3.0, jad 1.5.8g

I have followed the instructions in Installation and Troubleshooting but no matter what I do I always get the Eclipse class file viewer.

Browsing this forum I see this:

Binary classes (.class) must be in a folder inside the build path of a java project.
Otherwise you get nothing, neither an error log, and the class file is open with the original eclipse editor, even if you set as default jadclipse.

Now, my Eclipse project is set up to use a common build output folder, which is (must be, I believe) next to rather than under the source folder. Is it therefore not "inside the build path"? If that is in fact the problem, does this mean it is not possible to use this plugin with a common build output folder?

Second question (if I may :) I had hoped to be able to use this plugin as a general front-end for jad, meaning I could open any arbitrary class file (not necesarily part of my project) in Eclipse and see the decompiled source. Now I wonder if this is in fact not the design intent, and is not possible. Be this the case, can someone point me to a good visual frontend to jad (by "good" I mean better than cavaj or FrontEnd Plus)?