German wiki says Freetz has no support for it, Speed2Fritz has option but it says "for testing purposes only", but above all some Polish "eBay Fritz seller" [www.fritzbox.biz] claims that he has working 722 English multi annex firmware.
This Speedport seems to be direct alien of 7390 without some functions like DECT, S0 bus, gigabit ethernet etc.
Any ides for testing are most welcome.
I just got myself an Speedport W 700V, yes I know its not AVM, however it seems to be an very stable machine. I got Annex A working firmware for it and currently I am planing to an complete translation of it to English and Italian. If anyone is interested to do lecture of my Italian translation is most welcome.