[stuck]

I just changed my router to a ZyXel x550 for the QOS. I have my Sipura 2100 behind the router with provisioning turned off. My BV account is setup to simultaneously ring to my cellphone. But with the x-550 router setup, my BV phone will ring along with my cellphone. But when I pick up the BV phone line, it is just silence and my cellphone continues to ring until I hang up or pickup on the cell. Calling out is fine and if I turn off simultaneous ring from the website it works fine. At first I thought it was a BV issue but then I switched the router back to my old Dlink 514 and the issue resolved.
With the ZyXel I have the sipura on a static DHCP, and the streamengine set for "All" protocol (eg TCP/UDP) for that IP address x.x.x.110 set at highest priority. I've also tried putting the sipura's IP in the DMZ. Still doing the same thing. I haven't tried to upgrade the firmware yet. But I doubt that it would resolve my situation anyways.
Does anyone know what if any specific configuration eg routing table, virtual server, port forwarding etc...is required in the ZyXel router to allow the sipura to function properly???

[stuck]

Update...
I upgraded to the v1.3 router and now the problem was solved for a little while but now it has returned... no changes to the router config or the sipura config.
Seems to have resolved again now for past 3 hours after a reset of the router...
FYI