Hi Zimbra-users and admins!

I am in the urgent need for this topic:
The installation of ZCS 8.0 (Open-Source-Edition) on Ubuntu 12.04 in a virtual machine is finished.
Afterwards I created my users (4-5).

Before I turned off the old ZCS 7.2 server (also FOSS) I backuped the data using the command outlined on this page http://blog.zimbra.com/blog/archives...grations.html:
/opt/zimbra/bin/zmmailbox -z -m user@domain.com getRestURL "//?fmt=tgz" > /ADMIN/account[1-4].tgz
I copied the files to the new server and according to the migration page I tried reimporting with this command:
/opt/zimbra/bin/zmmailbox -z -m user@domain.com postRestURL "//?fmt=tgz&resolve=reset" /ADMIN/account[1-4].tgz
Importing small mailboxes with a size 35MB, 109MB, 129MB works great! ;-)
Importing bigger files 1.7GB, 2.1GB and 2.9GB results in this message, wether importing via CLI or webclient:

root@mail:/ADMIN# /opt/zimbra/bin/zmmailbox -z -m acc3@mydomain.de postRestURL "//?fmt=tgz&resolve=reset" /ADMIN/acc3.tgz
ERROR: service.FAILURE (system failure: POST failed, status=413 upload too large: file '/': upload too large)
I read a lot about setting some values to a higher value like these ones:

zimbra@mail:~$ zmprov gacf | grep zimbraMtaMaxMessageSize
zimbraMtaMaxMessageSize: 8796093022208
zimbra@mail:~$ zmprov gacf | grep zimbraFileUploadMaxSize
zimbraFileUploadMaxSize: 8796093022208
zimbraFileUploadMaxSizePerFile: 8796093022208
But it doesn't work!
I really urgently need my mailboxes imported and would be very very happy if someone could help out here, please!

Thanks a lot in advance,