Once added in vmware , rescan the scsi bus to see the new disk (assuming you use scsi disks)

find out which one to use

# ls /sys/class/scsi_host

Now use the value given (host0) in this case

# echo "- - -" > /sys/class/scsi_host/host0/scan

# fdisk -l

# tail -f /var/log/message

you should now see the new disk , sometime vmware tools does this for you!

Removing a disk

once the filesystem is unmounted , volume groups removed from it etc you can remove a disk like so:

echo 1 > /sys/block/sde/device/delete