Automount external LUKS device

I’m running KDE and I would like to use its automount feature but with an external LUKS device.

When I am not using automount the procedure is simple and works well. I plug the device, choose it in device tree in Dolphin, type LUKS password in appeared window and the drive shows in external devices tree, so I can open it.

When I’m trying to use automount feature, when I plug the device, LUKS password box appears instantly, I type the password but then I need to put another, root password, to allow mounting “luks-(UUID) device” .
Is there any chance to avoid putting root password like in manual method? I tried to mess with fstab and crypttab but with no luck (I’m not familiar with it).