Interesting followup to the followup. I have already booked my 2013 stay for this same conference at the property in Downtown Houston, and asked the telephone agent if this rate earned points, and she said it did. I went ahead and forwarded a copy of the reservation to the hhonors email address to ask them to confirm that as well. I received a response today with the following:

The booking will be eligible for HHonors earnings. Conference rates that are paid by the member are eligible for earnings. The exception would be bookings that are paid with a Master Bill. The other booking was noted incorrectly as an ineligible stay rate but it should have posted as eligible without your follow up. I apologize for the inconvenience.

So if you are having similar issues with receiving credit for a stay, you might ask more than once. Just sayin'l...