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Introduction to Outlook Web App Customization

Microsoft Office Outlook Web App for Microsoft Exchange Server 2010 provides a rich Web-based environment for accessing a user's mailbox, including e-mail, calendar, contacts, and so on. Exchange 2010 provides some important Outlook Web App customization features, including the ability to do the following:

  • Add custom forms.

  • Integrate other applications through navigation pane links.

  • Add items to the New drop-down menu.

  • Add items to the right-click (context) menu.

  • Integrate with other Instant Messaging server products.

Customizing Outlook Web App

Because Outlook Web App runs on all the computers in an organization that are running Exchange 2010 that have the Client Access server role installed, you must deploy any customizations onto all the Client Access servers that the users connect to.


The customization features that are provided in Exchange 2010 are not available in the light version of Outlook Web App.

Custom Forms Registry

When an Exchange-based application uses custom content classes that are stored in user mailboxes, the application must also seamlessly handle those custom content types inside Microsoft Office Outlook. Outlook supports custom forms for this purpose, and Exchange 2010 extends that support to Outlook Web App.

A custom form for Outlook Web App consists of custom .aspx pages that are stored on the Client Access server. An application that uses custom Outlook Web App forms will typically have one .aspx page for each action that can be performed on the custom content type, such as create, send, reply, and so on.

Outlook Web App in Exchange 2010 includes an XML file named the Custom Forms Registry. The default installation includes a template forms registry file that you can rename and then customize to fit the application. The forms registry file specifies how to handle custom content types by indicating what form to display when the user performs the actions that are indicated in the registry file.

To display a custom small icon for a content type, specify the icon file and content class in the SmallIconMapping section of the user interface customization file.

Customizing the Outlook Web App User Interface

You can more closely integrate custom applications by using two Outlook Web App user interface modifications in Exchange 2010.

To link to external applications or enable users to create new items of a custom content class from Outlook Web App, you can register new entries to the New drop-down menu. You can also add entries to the right-click (context) menu.

To enable access to Web-based applications from the Outlook Web App user interface, you can add entries to the navigation pane. This is useful when you want to provide access within Outlook Web App to applications that are loosely integrated with Exchange; for example, expense-tracking applications that store data outside the Exchange store.

Using Outlook Web App Web Parts

You can use components of Outlook Web App in your Web pages and applications by formulating URLs and then using the resulting HTML.

Customizing the Outlook Web App Theme

In addition to integrating custom applications, you can also modify the default Outlook Web App theme. You can change the colors, fonts, and images. For information about how to create custom themes for Exchange 2007, see Create a Theme for Outlook Web App on TechNet. Similar documentation for Exchange 2010 is not available at this time. For information about the differences between Outlook web application customization in Exchange 2007 and Exchange 2010, see Working with Outlook Web App Customization.

Changes in Outlook Web App in Exchange 2010

Many new features have been added to Outlook Web App in Exchange 2010. The following are the major changes that are relevant to Outlook Web App customization:

  • Custom forms can no longer be applied to folders. In Exchange 2007, you can use the Forms Registry to specify custom forms to render the content for folders and item types in Outlook Web Access. In Exchange 2010, you can register forms in Outlook Web App for item types only.

  • Custom forms cannot be used to display items in conversation view. To view items rendered by using custom forms, the user has to turn off conversation view.

  • You cannot select themes. Outlook Web App has only one theme, located in the …\Base folder. You can modify that theme; however, your changes can be overwritten by an Exchange 2010 update or service pack.

  • Outlook Web App cannot be used as Web parts.

  • Developers of Instant Messaging server software can integrate with Outlook Web App to provide presence and Instant Messaging capability.