This info is off top of my head - so just something to try (might not be correct for this appliance).
For some VMware appliances no matter what name you put in they will be reset on reboot, this is because a DNS reverse lookup is done on the IP address, and then whatever comes back is used (or a default used if a valid response is not returned)
ChrisF (VCP4, VCP5, VCP-Cloud) - If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful