Copy vm instance with custom volume to other server/storage?

Incus
1

When I try to copy a vm having a custom volume I can’t figure out how to get this done if on the target server storage pool names differ: source: ssd1, destination: zpool1

For me this seems to be a chicken/egg problem:

incus copy node04:zulip zulip --mode pull --refresh --storage zpool1 --config boot.autostart=false --device zulip-swap,pool=zpool1 --device zulip-swap,source=zulip-swap
Error: Failed instance creation: Failed creating instance record: Failed initializing instance: Failed add validation for device "zulip-swap": Failed loading custom volume: Storage volume not found

so I copied the volume zulip-swap first and then tried again but now I get:

zulip zulip --mode pull --refresh --device zulip-swap,pool=zpool1 --device zulip-swap,source=zulip-swap
Error: Failed migration on source: Error from migration control target: Failed creating instance on target: Cannot create volume, already exists on migration target storage

Maybe I have to overwrite config instead of storage?
How could I overwrite config device zulip-swap to use pool=zpool1?

2

I now tried to work around the custom volume issue by removing the custom volume on the source but now I realize, that the virtual-machine block volume exists on the target but not an incus instance:

incus list zulip --all-projects
+---------+------+-------+------+------+------+-----------+
| PROJECT | NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |
+---------+------+-------+------+------+------+-----------+


incus storage volume list zpool1 type=virtual-machine name=zulip
+-----------------+-------+-------------+--------------+---------+
|      TYPE       | NAME  | DESCRIPTION | CONTENT-TYPE | USED BY |
+-----------------+-------+-------------+--------------+---------+
| virtual-machine | zulip |             | block        | 1       |
+-----------------+-------+-------------+--------------+---------+

Since there is no command to delete a storage volume of type virtual-machine I guess I have to fix this directly in the incus db and on the zpool?