.vmem files in ESXi 5

  Hello,

  In VMware Workstation, taking a snapshot of a running VM would generate a .vmem file that was the image of that VMs memory. With ESX 5, I do not see a .vmem file. Insteat I see a .vmsn file that is slightly larger than my VMs memory. How can I get ESX to generate the same .vmem file? I need the exact content of VM's physical memory in a file, without any extra meta-data

  Thanks,

  Amin