On the VMware forums, Kevin Gehrke (a Senior Technical Support Engineer for VMware) posted a "how to" method for importing a VMware Server beta image into VMware ESX Server.

He writes:

First remove snapshots and make a backup of the virtual machine.

A unsupported option is to use vmware-vdiskmanager to convert your virtual disk into a type 1 (growable split into 2Gb file) or type 2 (Single pre-allocated) or type 3 (Pre-allocated split into 2Gb files)
Type 1,2 & 3 have a text file for the first .vmdk file, which is a disk descriptor file. You can edit the .vmdk file and change.

ddb.virtualHW = 4

to

ddb.virtualHW = 3

Note: Type 0 virtual disk would require you to use a hex editor.

You will need to use the virtual hardware wizard to remove your original virtual disk and add the one you converted.


Now edit the .vmx file and change the following from

config.version = "8"
virtualHW.version = "4"

To

config.version = "7"
virtualHW.version = "3"

Keep in mind that this is unsupported and use at your own risk.

Verify that the VM is working before exporting to ESX.

Read the original post and comments, here.