Ok, now I've seen and understood your "workaround", but you have to pay attention and press the "Back" botton after the initial form to install asking you the user/password, name of the PC, etc. Otherwise you can't see the "Copy function".
The problem is that you lose the chance to change user/password/name of the PC, etc. and might confuse users to select the right partitions. By the way, it would be helpful to see the label of the partitions.
Ok, now I've seen and understood your "workaround", but you have to pay attention and press the "Back" botton after the initial form to install asking you the user/password, name of the PC, etc. Otherwise you can't see the "Copy function".
The problem is that you lose the chance to change user/password/name of the PC, etc. and might confuse users to select the right partitions. By the way, it would be helpful to see the label of the partitions.