[Exim] Help with rejecting hosts problems

Hi all,

I have had Exim 3.3 running great for over a year and just started
getting clobbered with spam. So I added a few RBL's (see below) which
worked great but some stuff still gets through so I created an
additional list file that I can add IP or host names to as spam comes in
like:

host_lookup = *
host_reject = /etc/exim/host_deny.exim
...

which seemed to work fine, but reading the documentations it seemed to
imply the for spam it was better to use:

host_reject_recipients = /etc/exim/host_deny.exim

So I changed to this, then I noticed in my logs that some sites where
getting reject that I wanted to receive mail from, so I added:

recipients_reject_except_senders = /etc/exim/host_reject_except.exim

and added the name I did not want rejected to this list. But I noticed
in my logs that I am now reject all hosts that don't resolve a dns name,
so of which I want to receive mail from. reject log messages like:

2002-05-21 15:03:58 recipients from [12.124.4.118] refused (failed to
find host name from IP address)
2002-05-21 14:00:29 recipients from icomm.ca [216.126.72.23] refused
2002-05-21 08:27:58 connection from usw-sf-fw2.sourceforge.net
[216.136.171.252] refused

Here are 3 that were refused, that I wanted. What have I done wrong?

I tried to use:

host_reject = +allow_unknown:/etc/exim/host_reject_except.exim

to override this behavior. But things just aren't working the way I
expect them to, which is the real problem. I have read the documentation
and searched the archives but I haven't been able to figure this out. So
any help would be great appreaciated.

my rbl setup is:

rbl_domains = Relays.OsiruSoft.com/reject : \
              bl.spamcop.net/reject : \
              relays.ordb.org/reject : \
              list.dsbl.org/reject

rbl_hosts = !10.1.1.0/8:0.0.0.0/0

recipients_reject_except = postmaster@???

What I would ideally like to have is:
1) an additional list of hosts that are rejected
2) an additional list of hosts that are accepted
3) any other advice and comments on a better way to deal with these
issues

Thanks and sorry for being so verbose.
Best regards,
-Steve