Uninstall Office Standard 2010 during installation of Office ProPlus 2010

Hello,

Office 2010 Standard is installed on most of our Computers. Now we have to replace it with Office 2010 ProPlus.

I created a script which uses an MSP during the installtion. Here i configure, that all old Versions should be uninstalled.

See the attached screenshot (sorry ist in German).

Unfortunatly the Standard Version is not removed automatically.

 I added this unsinatll line to my installton script:

"%programfiles(x86)%\Common Files\Microsoft Shared\OFFICE14\Office Setup Controller\setup.exe" /uninstall STANDARD /config %~dp0Remove_Standard\config_uninstall.xml

and ist working if Office 2010 Standard is installed. But if ist not installed, I am getting a message which has to be apllied and so a sielent installtion is not possible.

Any ideas?