Unlike the header of a LUKS-encrypted partition, the header of a TrueCrypt/VeraCrypt-encrypted partition is also encrypted. So without knowing the encryption key, you should not be able to tell it from random noise, at least not without advanced statistical analysis.
As a result, automatic detection of VeraCrypt partitions is not possible.
Clonezilla can do a
dd-style raw copy from one disk/partition/image file to another, or a smarter filesystem-aware copy that can avoid copying any blocks that are currently marked as "free" in the filesystem. But the smarter methods need to be pointed at a recognizable filesystem, not at pseudo-random encrypted noise.
When you mount a VeraCrypt partition, two things happen.
First, a device like
/dev/mapper/veracrypt1 is created. This is the actual encryption/decryption layer: anything you write into it gets encrypted and stored in the actual VeraCrypt encrypted partition, which is probably something like
/dev/sdX1. When you read it, the corresponding location in the encrypted partition is read and decrypted. As a result, you can use the
/dev/mapper/veracrypt1 device just like a real disk/partition device and set up a normal filesystem on it. VeraCrypt does exactly that when you create a VeraCrypt-encrypted volume.
Second, the VeraCrypt tool will automatically mount the
/dev/mapper/veracrypt1 device to the place you specify, e.g.
When you want to use Clonezilla with a VeraCrypt-encrypted partition, that second step is actually something you don't want. You'd need VeraCrypt to just activate the
/dev/mapper/veracrypt1 device, and leave the actual filesystem unmounted so that Clonezilla can freely manipulate it. Apparently you can achieve it like this:
veracrypt -tc -t --filesystem=none <encrypted thing> <mountpoint>
--filesystem=none, the actual mount step will be skipped.
Then you can just point Clonezilla to
/dev/mapper/veracrypt1 just as if it was a regular unencrypted partition.