I just purchased a Garmin RV 770. I am trying to transfer waypoints, etc. from a Driveassist 50LMT. Garmin Express has a platform for this, however, when I select the device to transfer from, the TRANSFER button stays grayed out and will not perform the transfer. The Driveassist has been backed up to the prescribed directory on my computer. Any suggestions on how to make this work? I have another Garmin backed up as well, and it does the same thing on it.