On the Edit menu, point to New, and then click DWORD Value.
Type EnableLocalMachineVSTO, and then press ENTER.
Right-click EnableLocalMachineVSTO, and then click Modify.
In the Value data box, type 1, and then click OK.
Exit Registry Editor.
By default, VSTO-based add-ins are displayed in the COM Add-ins window. You have the option of hiding these add-ins in the COM Add-ins window by deploying the DontDisplayHKLMAddins registry entry.
For more information about the DontDisplayHKLMAddins registry entry, click the following article number to view the article in the Microsoft Knowledge Base:
929590 Known issues when you develop custom solutions for Office Outlook 2007
When you deploy both the EnableLocalMachineVSTO and DontDisplayHKLMAddins registry entries, the add-ins are listed in the Trust Center of a 2007 Office system. Additionally, you cannot remove the add-ins because they do not appear in the COM Add-ins window.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Microsoft Office Basic 2007, Microsoft Office Enterprise 2007, Microsoft Office Home and Student 2007, Microsoft Office Professional 2007, Microsoft Office Professional Plus 2007, Microsoft Office Small Business 2007, Microsoft Office Standard 2007