Now that I am at work, I can give some better info.
On main tab of DavMail's set up: I have turned on IMAP, SMTP, CALDAV HTTP and LDAP & specified ports.
As per my early post, I just create an IMAP account and 'point to' this IMAP server, which for me is just localhost
Also in evolution while setting up the IMAP account, in the sending email; i specified the SMTP server as the one provided by DAVMail (again local host) . I have no encryption turned on and do have 'requires authentication' on and 'plain' type and use my domain/exchange credentials..... Like with IMAP, the first time you send, EVO will ask for your password.
Address book & Contacts (NOTE
this took some trial and error to get it the way I wanted): I went to that screen in Evo, and created a new address book of type ldap. Again DAVMail is the ldap server. I marked as default; i have auto-complete on; I have 'using dn' and my domain/exchange name for the login (under authentication). My secure connection says SSL (which doesn't make sense to me as I have ssl off in davmail....). In the details tab I have search base as "ou=people" . <-- that took some trial and error. I vaguely recall using rdc to go to a real windows box and using outlook to browse my address book and look at contact details; and I saw this as a component of all my contacts DN....and just kinda guessed.
for calendar stuff: again in evo I went to calendar and create a new one and marked it default. I made it type CALDav and used a caldav url pointing to my DAVMail server like: caldav://my.localhost.com:1080/ the user name is my domain/exchange user name and I think I did 'browse' and selected my calendar. My URL now reads like this:
caldav://my.localhost.com:email@example.com/calendar/ I recall the calendar setup took some time and trial and error too.
And....one last thing.....for me, my OWA or something was setting some mime-type for attachments to a value that DAVMail (actually the mail lib that DAVMail uses) to a value that it didn't like. Assuming you are using 3.8.8-1608 of DAVMail you can edit the davamail.sh file to be like below to make this problem go-a-way (only bold stuff is added).
# Ubuntu setup instructions :
# install java :
# sudo apt-get install sun-java6-bin
# launch davmail :
for i in $BASE/lib/*; do export CLASSPATH=$CLASSPATH:$i; done
-cp $BASE/davmail.jar:$CLASSPATH davmail.DavGateway $1