Finally found the problem. I forgot to add a seam.properties file in my src folder to allow Seam to detect components.
Now it works fine.
I'm experiencing a similar problem. I also get NullpointerExceptions after setting up the eclipse plugin for TestNG, but, in comparison to you, I can locate my seam.properties file in /test-build. Does anyone know, why I cannot use Component.getInstance(...) though?
Thanks in advance for any hints