I've installed a few 5621 VPN phones and as soon as I've loaded the bin file to make it a VPN phone, the backlight stops working. This has happened to all the ones I've done. I've talked to Avaya Tier 3 and they tell me that theirs works and I can't get an answer on why mine do not or how to fix it. There is no documentation to be found anywhere. Anybody have any ideas on how to get the backlight to work on a 5621 VPN phone?