Not that this helps much since you already know about this now. These instructions detail upgrading the trailer. The grounding kit must also be done, to properly accomplish that, you must remove the paint where the ground lug is attached. Also, if you read the instructions, you can see that the amber turn signals are disabled. I suppose if you built your own module like the other guy did it should work.
Others have mentioned the lights run through the cluster and it is possible for the trailer lights to destroy the instrument cluster. Not exactly sure how it is wired and can do this, but that has been posted before.
I would think that if you retained the original amber turn signals, along with the original trailer harness, ensure the proper ground it is installed, then run an aftermarket electronics module capable of running all the lights, it should work. To connect, it may or may not require spicing into the Spyders wire harness. However, possibly, someone offers a plug and play setup for the electronic module as you want it.
Early on I mentioned checking the trailer to ensure this mod for the wiring and disabling the turn signals was not already accomplished. There is some changes made to the main connector of the trailer harness on the 2010 trailers. If the mod has been done, and you want turn signals, you may need to reverse that repinning of the connector.
Checking to verify if the trailer ground kit is installed is an easy visual check. Look underneath for the ground lug as shown in the instructions, and also check for the added bolt to the trailers tongue.
Since you mention having a good dealer, ask him also for a copy of the Spyder / Trailer / Electronics chart that lists the various combinations possible, and what is required to make the trailer of a certain vintage work with a Spyder of a certain model and vintage. Different combinations have different requirements. I was allowed to get this info so I knew what direction to proceed when I setup our 2012 RT622 with our 2014 RTS. All the correct stuff, correctly wired and grounded has worked well, although, we have shared brake / turn signals, which you do not want.
All the best, however you proceed.
These are the wiring mod instructions. The ground install instructions follow that. For me, the ground was accomplished as a recall.
http://instructions.brp.com/content/instruction-sheet/en_CA/e-instruction-details.html#articleNo=kA0a0000000dnvVCAQ&lang=en_CA&title=ROADSTER%20KIT%20-%20Trailer%20Conversion%20(2010-2012)&rel_part_number=219400637
http://instructions.brp.com/content...und Harness Trailer&rel_part_number=219400537
