virtualbox.org

(generic 105-key-keyboard; quertz, de; virtualbox-3.0 3.0.2-49928_Debian_lenny)

Some keys are not available in VMs - "not available" meaning, that they don't even generate
a scan code, so independent of the chosen keyboard layout, key events from those keys are
not visible inside a VM. The issue does not seem to depend on the guest OS; as far as I can
tell, it is the same with Linux,Windows or Solaris guests.

The most prominent missing (and missed ;-) key that I noted is "^", on German keyboard on
the left edge in the nuerical row; on the host system it generates keycode 49/keysym 0x5e
(asciicircum). Some other keys (mostly the "windows" keys) generate wrong or duplicate
keycodes inside the VM.

Does anybody know any details about the keyboard mapping between host and guest and
how to influence it?

The only correlation that I know of is when you install the guest and it asks you to define the keyboard.
If you accept the default maybe it is incorrect.
I do know that I had a VM from a German keyboard layout and it worked much as you say.
Changing the keyboard on the guest fixed it for me.

Also if you have not installed the guest additions it may effect this too. It is not supposed to but it does on accasion.