it was a policy problem. forgot to allow usb access for third party devices (something like that).
btw. i am not very happy with the coolmir support, they first did not answer for weeks, and on my latest question they did not response at all.
however, i won't give the keyboard out to users, because it only will work when there is no password
set on handheld.
that will, for security reasons, of course NOT be an option in my environment.
further, the input rate is very low. 60 keystrokes/min or something like that.