Hi..just on the COPY all message part of your Q
there is no in built zimbra function but you can use the age old POSTFIX "always_bcc" to archive all IN+OUT email to 1 account on the server
Here is how:
1) Create a USER on your domain i.e:
copyall@yourodmian.com you can name it anything
2) Edit MAIN.CF file and add the following line on top of the file or anywhere
always_bcc=copyall@yourodmian.com
* The “main.cf” file is at the following path..your postfix version could be different based on version of zimbra:
/opt/zimbra/postfix-2.4.3.4z/conf/main.cf
3) Restart zimbra service
Now you will get ALL emails IN+OUT of zimbra copied to "copyall@yourodmian.com" without any user intervention or they knowing about it
4) Now you can play with FILTERS under "copyall@yourodmian.com" and filter your emails based on RULES and fwd/file/redirect them as desired
For helpdesk..you can make MULTIPLE Aliases for 1 email box and FILE the emails using FILTERS in folder and i guess Zimbra webmail lets you reply using any ALIAS name
* username and passwd for the account is same in this case
Hope this helps
Raj