I don't think its a good idea to issue a reboot command inside a VM environment. The reason is, I believe if you do so, the VM OS will just stop all running processes like its going to reboot, but since its virtualized you are asking it to simulate a reboot, and in essence the VM is still running the OS just stopping everything. I recommend issuing a halt command instead so that it asks the OS to exit. I'm not sure if that is clear. I hope it helps.
As for the installation, I believe there is an option to continue with the LiveCD after installation, in which place you can then use the console to issue the command "restart -h now"