How to debug a DLL loaded from a Windows service EXE

I have a Windows executable service which loads two additional DLL’s. I can
attach windbg to the service but neither of my dependent DLL’s show up in
the sym module list so I can’t set any breakpoints in the DLL code.

Is there a trick to associating the DLL’s with the service EXE so I can
debug them all within the same process?

Thanks in advance.