From: VMware Communities
if you want to automate your backups in a script, you can suspend and restart your virtual machines using this sort of command
vmrun -T server -h https://:8333/sdk -u -p suspend "[standard] "
replace with the IP or name of the host server
replace and with the username/password you login to the VMWare remote console with
replace with the folder and filename of the .VMX file of the virtual machine you want to suspend. eg. if you have the virtual machine stored at "C:\Virtual Machines\WinXP\WinXP.vmx" then this parameter should be "WinXP\WinXP.vmx", presuming that "c:\Virtual Machines" is the path to your data store.
Replace 'suspend' with 'start' to restart the machine after the backup.
