[fetchmail]Fetchmail/rblsmtp/qmail

Does anyone know of a way to get fetchmail
to work with rblsmtp->qmail to filter spam?
Or will I have to do post smtp processing to get 
it done?
For rblsmtp to filter spam it checks the env var 
of "REMOTEHOSTIP" which gets set to the 
calling programs remote ip, which in this case, 
from fetchmail is 127.0.0.1. 
REMOTEHOSTIP can be set, but fetchmail 
would have to do that, for it to work, maybe via
a skip header option.