Pbx behind Fritzbox Wlan7050 remote problem!

Fritzbox7050 infront of pbxinaflash
Here is my scenario:
I have fritzbox wlan7050 as a router connected to my Cable modem.
Pbx server is connected to Fritzbox.
Fritzbox uses port 5060 as default so I can`t forward it to the server.
I have forwarded following ports to the server:
I set up an account with dyndns.com and set it up in fritzbox.
I have edited the sip_nat.conf to include:
I can connect locally without problem

1)However,I`m still unable to register from a remote device or computer or from a different ip range.
2)There is no sip.conf in my server.is this a problem and how do I create one?
3)How or where do or should I change the sip port in pbxinaflash to reflect the used port(5062)?

Any help or heads up will be well appreciated.

and I am curious… I looked through the manual for that unit. I don’t see it being (other than to use itself for a sip proxy/FXS/FXO device) the least bit friendly for port forwarding. Also, and this may be the root of the issue, I am not clear on setting a static address in the DHCP Server.

If you can’t set the address to a MAC… game over IMHO.