How I can configure that all incoming call from PSTN to be forward from operator station (DN) to a alternative station (DN), after business hours. In this case, there is not Unity System.
Have a look at "Time of Day Routing" on CCM it should do what you need and more;
Cisco Unified CallManager System Guide, Release 4.2(1)
From this doc;
Also check out this this excellent presentation on Time of Day Routing supplied recently by Tom (it includes a great step by step and examples);
Hope this helps!