How to configure Vlan for VMs on rhev-m

Hi there,

First of all, I'm using:

Rhev Linux server 6.5
Rhev Manager 3.4.3-1.2.el6ev
Rhev Hypervisor 6.5

I'm trying to configure Vlans on rhev manager for my VMs. I've created a new network called vm_net, and i've configured it with vlan ID. After I created it, Hypervisor lost connectivity with the manager (Of course, I did'nt configure Vlan tagging on rhev-h yet). When I tryied to configure vlan tagging on Hypervisor's admin screen, network tab, the interface appear like "managed" and I can't modify anything.

1) Can you please tell me which is the correct way to accomplish this target?
2) Is there any way to unregister Hypervisor from manager without reinstalling it?

Thanks for advanced!