Fritz 7390 open NAT on sr101

[mbrokof]

Hi,
I am Matthias and new here.

I've got a sky router sr101 with broadband unlimited. As it doesn't support voip I have a fritz 7390 behind which gets the internet from the sr101. Everythings works fine except the voip part. The 7390 has the ability to keep voip port open so seems to shoot packages to the sr101 every 30s. With sipgate Accounts everything seems to work well as the IP which the sr101 gets appears in the sip no. . With voiptalk that doesn't work. I can't can't Voiptalk working over the 7390. Voiptalk support asked me to open Nat on the sr101 as they only can identify the jnternal router address. Sky support wasn't really of any help with it. I read somewhere that I should 'restart the sr101 in order to get that configuration automatically. I tried but it doesn't seem to work. How can I get nat open to get the IP through to voiptalk?
Any help would be very much appreciated.
kind Regards
Matthias

[Isitme]

Probably the only way you will get it to work is by putting the 7390 in the Sky Hub's DMZ. Even then it may not work as it will be double NAT, but worth a try.