[libvirt-users] VirtualBox headless

Hello, I'm trying to use the VirtualBox/vbox driver together with libvirt 0.8.1 on a Ubuntu Lucid Machine, VirtualBox Release 3.1. The goal is to run the virtual machines headless and to connect using RDP. When starting a virtual domain using 'virsh start <domainname>' the GUI of VirtualBox will pop up and I see no option to prevent this. If X is not running, the virsh command will terminate with 'unknown failure'. I've found some hints on inclusion of the headless statement in the 'graphics' part of the XML definition file, but when I tree to adopt this, the editing of the file will crash. Has anyone achieved to manage VBox machines with libvirt on a headless server ? Thanks in advance for some hints or experiences with this issue, Christian