Don't bother transferring it, just bring both passports. I came into Suvarnabhumi last night for the first time since getting the DTV. I also needed a new passport while I was back home and had the visa linked to the old one. Brought both the old and the new with a laminated print out of my visa. IO didn't even want to see my old passport. She just scanned the QR code on my visa print out and stamped me in for 6 months. Happy days!