Hello,
I guess virt-viewer connects via vnc? If so I had a similiar problem with libvirt/qemu.
The solution was to set a keymap for vnc in the configuration. Not sure how that works
with virt-manager maybe there is a gui setting for it.
But with libvirt you can add something like this to the xml config (notice the keymap, de is german qwertz layout)
Code:
<graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1' keymap='de'>
<listen type='address' address='127.0.0.1'/>
</graphics>