What is the secret sauce to getting the eclipse 2.4 beta plugin to generate RequestFactoryServices?

I've installed 2.4 beta and am trying to figure out how to get the 2.4 plugin to find my already created DTO objects and all I get is 

when I click on browse it gives me a greyed out screen and says no entries available. When I manually enter in the directory, it says no entries available. 

Do these objects have to be JPA objects, or do I have to setup some kind of special configuration to my old projects? 

What magic am I missing? 

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