WDS: Can't get rid of prompt to choose OS you want to install

We did add the this section to the wdsclientunattend.xml but the default image selection is ignored and we are still presented with the screen to choose and OS.

 </Login>
        - <ImageSelection>
            <WillShowUI>OnError</WillShowUI>
          - <InstallImage>
       <Filename>engineerbuild.wim</Filename>
              <ImageGroup>Engineer Builds</ImageGroup>
       <ImageName>Engineer Build</ImageName>            
            </InstallImage>
          - <InstallTo>
              <DiskID>0</DiskID>
              <PartitionID>1</PartitionID>

The image installs sucessfully after manually selecting the OS and clicking next.
The machines are XP, do we need to do more to make it choose the OS so we don't have to stand around and wait for the selection screen?