I've tried this on two different machines. Ghost does not list these virtual drives as selections in the drive list in the backup wizard. The only exception seems to be if Ghost is installed in an encrypted OS partition. In that case, Ghost can image that mounted partition.

But it cannot, as far as I can tell, do what Truecrypt recommends here: http://www.truecrypt.org/docs/?s=how-to-back-up-securely in the section under System Partitions:
To back up an encrypted system partition securely and safely, it is recommended to follow these steps:

1.    If you have multiple operating systems installed on your computer, boot the one that does not require pre-boot authentication.

    If you do not have multiple operating systems installed on your computer, you can boot a WinPE or BartPE CD/DVD (i.e. 'live' Windows entirely stored on and booted from a CD/DVD; for more information, search the TrueCrypt FAQ for the keyword 'BartPE').

2.    Create a new non-system TrueCrypt volume using the TrueCrypt Volume Creation Wizard (do not enable the Quick Format option or the Dynamic option). It will be your backup volume so its size should match (or be greater than) the size of the system partition that you want to back up.

3.    Mount the newly created backup volume.

4.    Mount the system partition that you want to back up by following these steps:

        Click Select Device and then select the system partition that you want to back up (in case of a hidden operating system, select the partition containing the hidden volume in which the operating system is installed).

        Click OK.

        Select System > Mount Without Pre-Boot Authentication.

        Enter your pre-boot authentication password and click OK.

5.    Mount the backup volume and then use a third-party program or a Windows tool to create an image of the filesystem that resides on the system partition (which was mounted as a regular TrueCrypt volume in the previous step) and store the image directly on the mounted backup volume.

The answer to my question appears to be: No, Ghost cannot image a mounted Truecrypt volume unless the volume is a system volume that Ghost is itself installed in. Ghost, and other backup programs such as TI, appear limited to imaging physical drives, with the aforementioned exception.

A mounted truecrypt volume is really just a file right?

*.tc I think, no?

you copy just backup this file like any ordinary file, no?

(via drag-n-drop)

Do you run your O/S from a truecrypt volume?

It sounds like you do. You would be the only person  now who does this.

Truecrypt is very cool.

what verson ghost?

Shame that Lumet died.