I'm not sure exactly what you are trying to accomplish. I do this because I want to deploy a guest where the ISO used to install the guest is much smaller than the OVA which results from exporting the already installed ISO.
Put another way, I create an OVA that contains an ISO, a minimal VMDK and an OVF file. The OVF file describes a virtual machine suitable for installing the ISO along with the path name of the ISO and VMDK. When I deploy the OVA, it creates a virtual machine with the ISO attached to the CD-ROM. When that virtual machine powers on the first time, the ISO boots and automatically installs itself. On the next boot, the guest is booted instead of the ISO image.
The only way to accomplish this AFAIK is to create an OVF file that describes what you want to do and then use ovftool to create the OVA from the OVF and ISO. The command line is: ovftool --compress=9 /tmp/foobar.ovf /tmp/foobar.ova
When the ovftool, input file and output file are all on the same machine, there is no need for any of the silliness about user IDs and credentials.
MikeD