Just take a look at our Karaf integration tests for the 5.4 branch:
https://github.com/hibernate/hibernate-validator/tree/5.4/osgi/integrationtest/mybkexperience
We also use Pax Exam. You should be able to make it work if you follow what we did.
BTW, I see you mention the annotation processor in your dependency for the 2nd time, it’s not something you need at runtime. The annotation processor is used to check that the annotations you used make sense at compile time. You should only enable it when you build your project.