Yes, you should not just try, you should make it happen.
I agree with bug! Set up the appointment, let the C know your goal and inform your H of the date/time/location. If he comes and participates, great! If not, then you discuss what the C thinks is best for the kids. She will make a note that your H did not attend. You will have given him an opportunity to discuss without Ls involved. It is a win/win.
