You can use the integration options to make it more convenient to launch OVF Tool as a helper process to a client of the vSphere Web Services API, such as a script using Perl bindings.
If you use the --I:morefArgs argument, the values for --vmFolder, --network, --net, and --datastore are interpreted as MoRefs instead of names, as shown in the following example:
> ovftool --name=vm5 \ --I:morefArgs \ --net:VM Network=vim.Network:network-12 \ --datastore=vim.Datastore:datastore-17 \ c:\temp\vm1\ \ vi://root:@localhost?moref=vim.ResourcePool:resgroup-42
Use the --I:sourceSessionTicket or --I:targetSessionTicket options to authenticate with a session ticket retrieved from SessionManager.AcquireSessionTicket, when using the vSphere source or destination.