I am confused as what you are planning to do -
1) Are you planning to upgrade your VI3 environment to vSphere 4 and then upgrade to vSphere 5?
2) Ar you planning to used VMware Standalone Converter to Converter to convert the VM form VI3 to vSphere 5?
What might help is if your take a look at http://pubs.vmware.com/vsphere-51/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-51-upgrade-guide.pdf
I have also moved this discussion to a more appropriate forum -