On March 3, 2008 at 17:53, jlet said...
Ask support to change the command action flag from "Press"
(single transmission) to "Hold" (continuous transmission).
I had copied Harmony support on Panasonic's "nope" response and they did something - they didn't say what - that made it start working. I'm guessing it was what you said. Thanks for your response. I'm definitely going to have to remember that for the future!