[exim] local_scan() before av_scanner

I wonder if I could use local_scan() function before scanning for
viruses with av_scanner
I'm scanning for spam with local_scan(), and I want to discard spam
message before it goes to antivirus because of it's per-message based
licensing limitations
how can I implement this ? Or it's so by default ?

--
Dmitry Pryadko
hosting.rbc.ru