Need to create a differencing disk from a disk chain

[moiztankiwala]

I have the following virtual disk structure for my virtual machine:

Base Disk [Immutable] => Child 1 [Readonly] => Child 2 [Readonly] => Child 3 (Auto reset = false)

Child 3 is currently attached to a virtual machine.

Now I need to create another virtual machine that is attached to Child 2 above via a new differencing disk. i.e.

Base Disk [Immutable] => Child 1 [Readonly] => Child 2 [Readonly] => New Child differencing disk.

What this means is that I need to create a new child differencing disk from the middle (off child 2) of the existing chain. How do a I go about doing that.

My problem is that when I create a new virtual machine via the UI and add an existing hard disk, the only option that I see is the base disk which is immutable. When I add this immutable disk and check the "diferencing disk" check box, a new differencing disk is crated right off the base disk (immutable) and I have no way to choose child 3 as the parent for the new differencing disk being created.

I have searched all over and cannot find any means to create a differencing disk from the middle of the chain.

Thanks for looking up my problem.

Regards,
Moiz Tankiwala