I am first time using zimbra mail server. our mail administartor left the organization and now i have to handle it.

We are using zcs 4.5.10 on RHEL 5 - 64 bits in production environment. And right now one domain is running on this server and its working fine.
We are providing 100 MB mailbox quota and 10 MB attachment size for this client.

Right now we got another client with different requirements. Those are as below:

1. They need 15 MB size limit for attachment
2. 1 GB mailbox quota / user
3. Blackberry configuration for critical users
4. Mail quota warning of user should go to user as well as administrator. ( just like mail quota size monitoring for all users and ofcorse need prompt action if it exceeds )

So my questions are as below :
1. is it possible to set different attachment size to different domain ?

2. I think we can set different mailbox size per user and per doamin in zimbra..but need to confirm.

3. is it possible to configure blackberry on zimbra ? i couldnt find any proper procedure for this on net. is there any link ?

4. in current configuration if user exceed his mail box size then he gets quota warning from zimbra. but in this domian they want to send warning alert to administartor also means to me so i can monitor it and do require steps. is it possible in zimbra ?

I am still reading all stuff on interent and forum but due to lack of time i dropped this thread as need to submit plan and confirmation asap to management.
Please guide n help.