Loss of sync with UpDown Cross

I am having trouble with the BM Mini UpDownCross converters when upconverting a signal that is locked to my house reference. In going from 480i to 1080i the signal becomes unlocked or non-synchronous. The image is not distorted and there are no embedded audio concerns with this signal. This happens with or without a black burst reference signal supplied to the UpDownCross and has happened on two different units.

Any suggestions are greatly appreciated.

Updating my own thread ... The BM support staff is telling me that I need tri-level sync for any upconversion to HD were the signal needs to maintain reference lock. If anyone can confirm this for me I'd greatly appreciate it. I'm not wired for tri-level and distributing reference for this product alone will be difficult.

Thanks,
Roger Sherman