Exchange 2010 SP2 Internal-External Access Problem

Hello

We have installed Exchange Server 2010 SP2 to our network.

We want to access the Exchange via Outlook from the internal network (MAPI, POP) and from the internet (Outlook Anywhere, POP, IMAP)

So, we have bought a public SSL Certificate from GoDaddy for the access from the internet. After we installed it to exchange we assign it to IMAP,POP,IIS,SMTP services. We deleted the selfsign certificate exchange had. So the can access the exchange from the internet without problem.

The problem is from the internal network because outlook will look for the autodiscover service which points to the internal fqdn exchange server name and there is no such a certificate. So we created a second virtual directory for owa,ecp,oab with a second ip address and give it a internal certificate for the internal fqdn exchange server name.

So outlook from the internal opens without any problem but we cannot download oab (this error “(0x8004010F) : 'The operation failed. An object cannot be found”)

Where is the problem? Is the whole procedure correct?