Yes in Windows I could assign other com-port numbers to the connector but 3 till 12 are "in use" according to windows and could not be assigned, com 1 and 2 didn't work correctly in winbird either.
I've fixed the problem now by resetting all previous com-port assignments:
http://www.bisque.com/sc/forums/p/446/430.aspx
freeing up the lower number com ports. assigning such a freed up number to the connector fixed the problem and vizard connects to the fob again.