JavaFX IDE SDK should contain:
1. Runtime binaries (the feature we have now)
2. Sources binaries (it needs to be added)
3. Documentation (optional)

To build SDK we need:
1. Add properties for source feature generation to build.properties of current feature JavaFX IDE feature
2. Create JavaFX IDE SDK Feature which includes:

    * current JavaFX IDE Feature
    * generated source feature defined in point 1 inside build.properties
      3. Adjust build script to build JavaFX IDE SDK feature
      4. Adjust update site to include JavaFX IDE SDK Feature

The source features/plugins generation is covered by "PDE Developer Guide" see here http://help.eclipse.org/galileo/index.jsp?topic=/org.eclipse.pde.doc.user/tasks/pde_source_generation.htm