Hello there !
'Donno if this will help but if there is someone with an EDIMAX 3G-6200n rooter which does not accept the K3772-z modem (mine's on VodaCom) - here's an answer.
I emailed Edimax support and received the upgraded firmware and nifty easy to use instructions on how to upgrade my firmware. Once upgraded, the new modem and rooter worked like a charm.
I have zipped the files I received and placed them here : www.vir2l.co.za/downloads/edimax.zip (3.7mb) if anyone wants to upgrade firmware for the EDIMAX 3G-6200n rooter.