Almost 10 years later and this post still proving to be incredibly valuable!
I studied this entire thread (and several others) for weeks before pulling the trigger on this project. It sounded much more difficult...so I was a bit nervous.
But I completed this today on my new-to-me 06 4.8is and was pleasantly surprised at how quick and simple it turned out to be!
Turned off my DRLs with BMW Scanner 1.4.0 (PA Soft). Upgraded my AE bulbs to LEDs. Tapped the white AE wire on each bulb right at the plug. Ran a 16g wire from each of those taps to the ECU in the engine bay. Tapped the other end of both into the red/white switched power wire pictured in post #1. This was the "alternate/best method" as recommended also in post #1. Buttoned everything back up and it all worked like a champ!