[Serusers] CPL and call forward on busy or no answer

Hi! I've successfully tested a handful CPL based services on SER 0.8.12 and most of them are working correctly. Only call forward on busy and/or no answer doesn't work. Enabling logging (debug=9) I get no error messages in the log file, but a NOTICE message that no lookup domain is given ("cpl_init: no lookup_domain given -> disable lookup node"). It seems to me that all services with blocking (i.e. call screening, time of day screening) and direct redirection to another host (i.e. call forward unconditional, time of day routing) are working correctly. When SER first tries to reach a client before redirecting to another host (i.e. call forward busy or no answer) it seems that the proxy server doesn't returns to CPL script execution. Does anybody no a reason for this behaviour or has a correct working CPL implementation for call forward on busy or no answer? many thanks, Oliver