The Microsoft limit for PST's is now 16GB - please expand your product line to allow for the increased PST size during exports from the DA product.
DA 10.x guide states :
The maximum size that CA or DA will export is 1.5 GB when using a supported version of Outlook on the CA or DA server" on page 155.
The current permissable PST file sizes can be found here:
http://support.microsoft.com/kb/832925
Creating multiple PST files for an export is problematic from a tracking and maintenance point of view.
Thanks,
Tom Simmons