The current implementation doesn't allow it to extend Vaadin Applications which are published as services using the com.vaadin.Application interface.
Implementing this would also enable to extend blueprint powered applications.
Furthermore a sample should be provided to demonstrate how this works with blueprint.
I was faster than I expected and a first implementation of blueprint support + sample application is ready.
I also did some cleanup and refactoring. Mainly this affected the ussed constants.
I already did a Pull-Request on GitHub.
pull request was merged