following on from my last post, thiis is from Wiki
"The Outlook Web Access interface available since Exchange 2000 comes in two flavors, one with a complete feature set (known as "Premium") and one with reduced functionality (known as "Light" or sometimes "Lite"). Prior to Exchange 2010 "Premium" access required
Internet Explorer. Exchange 2000 and 2003 require
Internet Explorer 5 and later
[1][2] and Exchange 2007 requires
Internet Explorer 6 and later.
[3] Exchange 2010 requires
Internet Explorer 7 or later,
Mozilla Firefox 3.01 and later,
Google Chrome or
Apple Safari 3.1 and later for full functionality, however performs checks on the operating system type to restrict Mac OS X and GNU/Linux users to Firefox or Safari, thereby making Google Chrome only officially compatible on their Windows operating system even though there is very little difference in their JavaScript and rendering capabilities between platforms.
[4] In all versions of Exchange, the "OWA Light"
user interface (UI) is rendered for other browsers. While the basic interface did not support search with Exchange Server 2003, the UI has been reworked for Exchange Server 2007 and OWA Light now supports search for mail items, and managing contacts and the calendar has also been improved.
[5][6] On Outlook Web Access 2010, a user is now available to connect email accounts on their Outlook Web Access. That feature is most ignored due to
professional uses of Outlook Web Access."
So, Exchange 2010 will give the Premium version of OWA on Windows with Chrome, but not on OSX, Lunix or Unix. There you need to use Safari or Mozilla.
Earlier versions of Exchange need IE
PS - this site gives a list of compatible OS versions and client programs for Exchange 2010.
Exchange 2010 Supported Clients
If you are using a Unix, the answer would appear to be to use Firefox with OWA, or else use Evolution