Cloning VLAN interfaces

[jammin2night]

FreeBSD charon 9.0-STABLE FreeBSD 9.0-STABLE #14 r233107: Sun Mar 18 
05:26:58 EDT 2012     root at charon:/usr/obj/usr/src/sys/CHARON  amd64

Hello:

I have a machine that has a 802.1q trunk attached which works fine.  I 
can create VLAN interfaces, apply an IP address to them and all is good.

I have VirtualBox running on this machine and need to present an 
interface to a VM that does not support trunking natively.  I've googled 
and searched the archive trying to figure out how to create an interface 
that VirtualBox will use where the 802.1Q tags are removed but have not 
had any success.

I attempted to create a netgraph interface like:

#!/bin/sh

ngctl shutdown re0:
ngctl mkpeer re0: vlan lower downstream
ngctl name re0:lower vlan
ngctl connect re0: vlan: upper upstream
ngctl mkpeer vlan: eiface vlan10 ether
ngctl msg vlan: addfilter '{ vlan=10 hook="vlan10" }'

but this nuked my VLAN10 interface.  Using tcpdump I saw no traffic on 
interface VLAN10 or interface ngeth0. I probably going about this all 
wrong or just don't get the netgraph hooks.

If there is an example as to how to this this I just missed it.

Any pointers on how to accomplish this?

Thanks.