How to create VLAN-tagged Network for a subnet that already has an untagged Network.

 My Enterprise Controller is attached to a particular VLAN with the switch port set to be untagged. I need to use Ops Center to provision an OVM/SPARC host on the same VLAN, but with tagging enabled. So the end goal is something like:

EC

IP:  10.12.34.12

Subnet mask 255.255.252.0 (/22)

VLAN tagging: NONE

OVM Host Control Domain

IP: 10.12.34.108

Subnet Mask: 255.255.252.0 (/22)

VLAN tagging: ID 1234

(Interface: Aggregation of net0 and net1)

The Ops Center 12cR1 Feature Reference, section 7.7.6 says that "The same CIDR can support both an untagged network and a tagged network.". The untagged network was auto-created when the EC first started & configured itself. I have tried to create a tagged network with the same CIDR mask, but instead it seems to just edit the existing network to have a VLAN ID set. When I actually provision the OVM/SPARC host (with Solaris 11.1) and tell it to use the "tagged" network, it creates interfaces with no VLAN tagging set.