Not that its of much help, but I too purchased the Phantom 2 with Zenmuse 2d gimbal option earlier this year as I read of the future firmware upgrade which would allow remote start/stop. ( remote recording was one thing I was looking for ).
I have been recently been emailing DJI regarding this subject, to which the replies were initially that 'they were not aware of what I had read' and 'could I give info of the link'. I forwarded the snipped copy of their DJI webpage with the paragraph stating the future firmware upgrade to allow remote start/stop recording. ( which was still showing on their site up until a few days ago ). Their response was that 'he would contact their PM, and get back to me'.
I have not heard anything yet, but 'strangely' on visiting their website today, the particular paragraph has mysteriously disappeared from the product information. I have today re-emailed them after spotting this change, to get a confirmation. but it doesn't look hopeful. I am personally annoyed, as my initial purchase of this over the vision/ waiting for a vision upgrade, was based on the fact that the gopro would allow this function with the firmware update. ( and give a better picture than the vision ), and I believe that although I am happy with the video/ photos I gain, I have been mis-sold this product if they don't have any intention of upgrading the firmware.
I know I can start recording prior to flight, but that's not the point. If it also something that you were expecting, may I suggest that if you haven't already done so, you also consider emailing DJI. Perhaps if they do get enough aggrieved people emailing, they may still consider doing something. The issue will be I presume be the same for the new 3d gimbal anyway, so the fact that they have released this hopefully wont make a great difference to this issue.
I will let you know of any further correspondence I receive.
Ian