One of the most expedient methods to solve a problem like this is to take the version of Seam you are running, create an example seam-gen project, create an new action 'seam create-action' which will generate and corresponding test, run that test, then tree the structure of the seam-gen'd project and compare with your own.
Well, my project was built using seam-gen. But just to try it out I ran it on another project, and they both have the same structure. Using create-action only creates the test it does not configure the classpath, so the same problem arises.
How can I add my components so the embebed container deploys them?
Well, I was running my tests using eclipse run dialog. When I tried the ant task, it compiled the classes and put on my test-build folder, now I can execute the test. This was the last piece of action needed.
Right, the Eclipse Run dialog to start the TestNG test will only be viable if you have a Seam Web Project created from JBoss Tools.