title: WebAppPool fails if AppPool already exists - WiX 3.5
body: <p>This was working in WiX 3.0.</p>
  
  <pre><code>&lt;Directory Id="TARGETDIR" Name="SourceDir"&gt;
    &lt;Directory Id="inetpubDir" Name="inetpub"&gt;
      &lt;Directory Id="wwwrootDir" Name="wwwroot"&gt;
        &lt;Directory Id="INSTALLDIR" Name="DS3000Services" FileSource="\Server\Implementation\DS3000Services\Web"&gt;
          &lt;Component Id="DS3000ServicesVirtualDir" Guid="{4EFD7047-09F4-42e7-ACB5-A209D26B0338}"&gt;
            &lt;CreateFolder /&gt;
            &lt;iis:WebAppPool Id="AppPool" Name="[AppPoolName]" Identity="other" User="PortalUser" IdleTimeout="0" RecycleMinutes="0"&gt;
              &lt;iis:RecycleTime Value="1:00" /&gt;
            &lt;/iis:WebAppPool&gt;
            &lt;iis:WebVirtualDir Id="DS3000ServicesVirtualDir" Alias="[VIRTUALDIR]" Directory="INSTALLDIR" WebSite="DefaultWebSite"&gt;
              &lt;iis:WebApplication Id="DS3000ServicesApp" Name="DS3000 Services" Isolation="medium" WebAppPool="AppPool" /&gt;
            &lt;/iis:WebVirtualDir&gt;
          &lt;/Component&gt;
  </code></pre>
  
  <p>Install Log:</p>
  
  <pre><code>MSI (s) (10:E8) [09:57:58:553]: Invoking remote custom action. DLL: C:\Windows\Installer\MSI14A0.tmp, Entrypoint: WriteIIS7ConfigChanges
  WriteIIS7ConfigChanges:  Error 0x800700b7: Failed to add appPool element
  WriteIIS7ConfigChanges:  Error 0x800700b7: Failed to configure IIS appPool.
  WriteIIS7ConfigChanges:  Error 0x800700b7: WriteIIS7ConfigChanges Failed.
  CustomAction WriteIIS7ConfigChanges returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)
  MSI (s) (10:4C) [09:57:58:585]: User policy value 'DisableRollback' is 0
  MSI (s) (10:4C) [09:57:58:585]: Machine policy value 'DisableRollback' is 0
  Action ended 9:57:58: InstallFinalize. Return value 3.
  </code></pre>
  
  <p>Installing on Win Server 2008 R2. The AppPool already exists. If I remove the AppPool, the installer succeeds. Any thoughts? Thanks...</p>