[opensuse] halt / reboot waiting time

I have a "small" problem, when the system goes for shutdown or reboot, the waiting time is too short for a process. I run a VMware on the system, it can take up to 7-10 minutes to shut down all VMs properly, and the system is too eager to shut down. So, before VMware has finished its shutdown properly, SUSE kills the processes which results in heavily screwed up disks in the VMs. How can I extend the waiting time for shutdown/reboot so that VMware can exit properly? -- Anders Norrbring Norrbring Consulting