In some cases it may be necessary to have the default OWA site require manual authentication (forms based or basic), specifically if your users use it to access multiple Exchange accounts. At the same time, I have found myself trying to become less dependent on fat clients and try to rely on thin clients where available and functional. And having Integrated Authentication turned on for OWA makes using that interface much more convenient for daily use. that case, it is necessary to create a secondary OWA site in Exchange that can be easily pinned as a web app and not require manual authentication. 

The first step is to create a new site in IIS to host the second OWA instance, as it is not possible in 2010 to have multiple OWA instances within the same site. Therefore, the second site will either need to answer to a new URL or at minumum a different port. I chose to set it up on a different port.

  • Open the IIS Manager and drill down to Sites, right click on the site folder and choose "Add Web Site". Enter a Site Name, physical path and binding information as shown below: