jakez, you need to flash your burner with Liggy's AD-7170S Bitsetting Firmware 1.03. After doing this (and rebooting the computer of course) ImgBurn automatically booktypes +R media to DVD-ROM on Optiarc drives
freddes, you also need to flash your burner with the bitsetting firmware, look in Liggy and Dee's website
donta beat me to it