Today I found the proper way to recreate the Virtual Directory.
Step one is to view all of the Virtual Directories on the server.
Get-OwaVirtualDirectory will display a list of all the Exchange Virtual Directories on that server. The one you are looking for
here is “OWA (Default Web Site)” on a default install.
Step two is to remove the default OWA Virtual Directory with:
Remove-OwaVirtualDirectory -identity “owa (Default Web Site)”
The next step is to recreate the OWA Virtual Directory with:
New-OWAVirtualDirectory -OWAVersion “Exchange2007″ -Name “owa (Default Web Site)”
Now go into the Exchange 2007 Management Console and setup the correct internal and external URLs and any other settings you may have
changed the first time around. One of the changes I recommend is on the “Authentication” tab the Logon Format for Forms based authentication to “User
name only” and then setting the domain. This will make it easier for your users to login by not having to remember the domain or typing domain\username.