The only way to re-size in ESX3 is with Converter. Vmkfstools no longer supports shrinking a disk, only expanding it. To get Converter to create separate disk files you need to run it twice, select the first disk only on the first conversion and re-size as needed then run the conversion again and select the second disk only and resize as needed. Once complete just copy the second disks vmdk file to the first virtual machine and add it as a hard disk. Then delete the 2nd virtual machine.