If I understand you correct, you want a pointcut that finds all methods in classes that extends MyService and is annotated and with the preferred arguments.
I propose that you replace:
execution(public * com.mycompany.myserviceimpl.*(..))
with:
execution(public * com.mycompany.myservice.MyService+.*(..))
The plus sign is used if you want a joinpoint to match the MyService class or a class that extends it.
I hope it helps!