From your description you have a leak in one of the covers - not uncommon. The link below is for chrome covers (example only may not be for your bike) evidently one of the covers is warped and the gaskets that go between them won't seal the interface.
You might get the Genuine Harley-Davidson Service Manual specific for you year and model bike. The Parts Manual for you bike will also be very helpful. Repair of a rocker box leak isn't too difficult.
The service manager should explain (show) you exactly what is wrong with your bike when you take it in for service. If you can't see the leak, I'd ask more questions.
If it is one of the gaskets above the head leaking they are easy to fix. I had to replace mine when I had my 99' 1200. I would get the manual for your year and you may need to cut down an allen wrench to get to one of the bolts (dependent on year). Also, I would would do both cylinders at the same time because when I did the rear the front started leaking two weeks later.