CRXDE does not support the Java annotations which are listed in the documentations. When you want to leverage CRXDE (which is for development ... discouraged), you need to migrate to JavaDoc style annotations.
For documentation how you can setup a development workflow based on a Java IDE and maven please see .
Can you check in the error.log, that your workflow step is properly registered as service?
There was nothing in the error log.
But now I could successfully add the workflow step by creating a bundle with the Eclipse-plugin m2e. Then, because I couldn't figure out the difference between the two of the bundles, I stored the CRXDE-bundle to harddisk and installed it via OSGi-console - this works. It seems, the CRXDE-bundle needs to become registered by some handling; it isn't done automatically.