Integrating Windows-API-Code-Pack in Outlook Add-In - Manifest unselectable

Question

I need to use the TaskDialog provided by the Windows API Code Pack in my Outlook Add-In. I recived this error:

TaskDialog feature needs to load version 6 of comctl32.dll
but a different version is current loaded in memory.

I followed the steps provided in the MSDN. I added a resource file and inserted the provided code:

<?xml version="1.0" encoding="utf-8"?>
<asmv1:assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1" xmlns:asmv1="urn:schemas-microsoft-com:asm.v1" xmlns:asmv2="urn:schemas-microsoft-com:asm.v2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <assemblyIdentity version="1.0.0.0" name="MyAssemblyName.vsto"/>

    <!--Enable themes for Windows common controls and dialogs (Windows XP and later)-->
    <dependency>
        <dependentAssembly>
            <assemblyIdentity type="win32" name="Microsoft.Windows.Common-Controls" version="6.0.0.0" processorArchitecture="*" publicKeyToken="6595b64144ccf1df" language="*" />
        </dependentAssembly>
    </dependency>
</asmv1:assembly>

I know I have to select the manifest file in the project properties, but sadly, the controls to select the manifest are disabled:

I need a solution, so I can use the TaskDialog.