Windows SBS 2008 and outlook access 2007

Hi I need help its urgent so please can someone reply to this,

I have one server with sbs 2008 and access 2007 installed in it. When I am trying to access OWA internally its working fine but when I am trying to access from internet its giving an HTTP Error 404. The requested resource is not found.
I am having netgear firewall and I have temp disabled it and also given exception in windows firewall.
I have tried to removed virtual directories and also Exchange and reinstall it.
I am using self made certificate and form based authentication.


Thank you in advance

For your information, Outlook Web Access is managed on the SBS Console on the Shared Folders and Web Sites tab. Whereas, OWA can be enabled or disabled and more importantly, individual permissions managed so that certain users can be given access to this mechanism while others are not. You might be not knowing that Outlook uses RPC over HTTP in order to access your email account on the same internal network. However, an Internet connection must be established prior to running the Outlook application.

thank you sir for your reply. I have set the permissions and rpc over http is enabled and also internet is always on.
but the error is
the requested URL /owa was not found on this server.

could you please guide me its urgent and if you could provide me your contact number so i can contact you.

thank you in advance
waiting for your reply