If you are using Windows XP or Windows 2003, you need to include the Sysprep packages in the vCloud VM.
Download the latest Sysprep packages from www.microsoft.com.
You only need to download the Sysprep files for any systems older than Vista and Windows 2008, because in these versions the Sysprep tools are stored locally on the OS. Check the VMware KB 1005593 for locations and direct links to the Sysprep packages. However, ignore the directory names the KB gives, as vCloud uses different ones from vSphere.
Don't forget that XP and Win2003 come in 32 bits and 64 bits respectively, and the Sysprep packages are different, so you may need to download both. We also need a means to transfer the packages to the Linux OS of the vCD VM; therefore, an SCP program such as WinSCP would be useful.