I hope this is a genuine bug so that it won't be an embarassment to me

I have a linux distro firewall/router - 192.168.10.10
My SME6b1 Server-Only - 192.168.10.15
I've already specify in the settings that the Master DNS is the firewall/router at IP address 192.168.10.10 but in the 'server-manager', under 'review configuration' -> 'server names' -> 'dns server', it is the local server 192.168.10.15
I've tried retyping the settings and rebooting several times but to no avail. The SME6b1 machine now is unable to communicate due to wrong DNS server setting.
Anyone can recommend a workaround? I'm e-mailing this to smebugs@mitel.com too, but I hope someone can shed some light in this matter..
Sincere regards and thanks all!