Unfortunately exporting/importing OVFs doesn't have an option (at least I'm not aware of it) to maintain such settings. What you may do is - when exporting the VM as an OVF - also download the VM's .vmx and .vmxf files. After re-importing the OVF, remove it from the ESXi host's inventory, upload the two *.vmx* files and add the VM back to the inventory. Then - once asked whether you copied or moved the VM on the first power on - select "I moved it".
André