Microsoft UAG 2010 offers a very flexible way for customizing different pages and settings. The UAG Customization mechanism is deployed using a “CustomUpdate” Folder structure. Under the “Microsoft Forefront Unified Access Gateway” folder tree you will notice that several folders contain this “CustomUpdate” folder, in this folder the UAG admins can create their own Files and place them in the CustomUpdate folder. 

When the UAG is activated it checks these folders first before checking the default folder. Its highly recommended to try all your customizations in this Folder “CustomUpdate” and the main reason is that if things went wrong, you can just delete these files and everything will be back to the default state before customization. Most of the Customization done for the UAG portal is done via the PortalHomePage folder as per attached screenshot.

UAG 2010 Customization Folders

An Example of Customization that I came across lately is the ability to increase the width of the Portal Home Page Left Side Menu. To Increase the Left Side Menu are you need to do the following:
  1. On the Forefront UAG server, open the folder Microsoft Forefront Unified Access GatewayvonPortalHomePage
  2. Copy the file Standard.Master to the folder Microsoft Forefront Unified Access GatewayvonPortalHomePageCustomUpdate.
  3. Go to the Below section and modify the Width Portion <td class=”midTopSideBarCell” style=“width: 200px;“> then Activate the UAG and test the change.

<td class=”contentLeftSideBarCell” id=”LeftSideBarCell”>
                            <table cellpadding=”0″ cellspacing=”0″ class=”leftSideBarTable”>
                                    <td class=”leftTopSideBarCell”>
                                    <%– Folder View Title –%>
                                    <td class=”midTopSideBarCell” style=”width: 200px;”>

This will increase/Expand the left Side Menu however the Bottom scroll bar is not automatically sized according to the main cell, to adjust it to automatically size/fit with the main left area you will need to customize the Office.css (Thanks to Microsoft team) file as follows:
  1. On the Forefront UAG server, open the folder Microsoft Forefront Unified Access GatewayvonPortalHomePageApp_ThemesOfficeOffice.css
  2. Copy the Office.css file to the vonPortalHomePageApp_ThemesCustomUpdateOfficeOffice.css
  3. Go to the below section (.SideBarContent) and modify the Width from 165px to 100% as shown below. Activate the UAG and test the change. This will automatically adjust the scroll bar to fit the left area in the portal.
Office CSS side bar content UAG Portal Customization
A very good reference is Technet Article of Customizing the Portal and Ben Ari/Rainier Amara Latest comprehensive book dedicated for UAG 2010 Customization.