Spliting TGZ exports

[UEDan]

So, I've been happy with Zimbra 6, great software. Been recommending it to a few IT peeps. Stable, but when it takes a dump it takes a dump. Restoring has been a bitch to say the least.

Can't do a imapsync, old server is down.

Command line gives me a:

[] INFO: I/O exception (java.net.SocketException) caught when processing request: Broken pipe
[] INFO: Retrying request
ERROR: zclient.IO_ERROR (Unbuffered entity enclosing request can not be repeated.) (cause: org.apache.commons.httpclient.ProtocolException Unbuffered entity enclosing request can not be repeated.)

For sure its because of the sizes, lets just say LARGE.

Tried split, retar and rezip portions of it, this is the error:

ERROR: service.FAILURE (system failure: POST failed, status=500 system failure: zip formatter failure)

So whats the correct command to split those huge mailboxes?
It works PERFECTLY on version 5, so what happened?

Right now I have to restore on a Zimbra5 server then imap over, still working on it, WAY to damn slow.

Please, what is the best way to restore a LARGE inbox, and please, please please, fix that import bug. 7 doesn't work either.

Thank you.