[exim] Best bogofilter integration (for after-SMTP time)?

Hi,

I've seen two way of integrating bogofilter:

o as a transport_filter for (almost) each transport
o as a transport of its own resubmitting the mail into exim's queue

Both methods are kind of hackish. The first one needs redundant
settings that are error prone, the second adds superfluous Received
lines to the headers.

All I want is to pipe the mail into bogofilter and get bogofilter's
Header back and add it to the mail. What is the best way to do so?
Recipes are welcome!

Thanks!
--
Axel.Thimm at ATrpms.net