DVS Controller + vif-locking-mode=locked

I faced with problem of rogue DHCP server, that gives to VMs wrong IP addresses.

I found only one solution for XenServer to prevent rogue DHCP server.

It is DVS Controller.

I deployed DVS Controller from Xenserver 7.5 and set policy to block rogue DHCP server.

Now it is all OK with DHCP, but now I can not set vif-locking-mode=locked because of error

"You attempted an operation that was not allowed.
reason: A vswitch controller is active"

At same time I can set any other "vif-locking-mode" type (unlocked,disabled,networ-default), but not "locked".....

So, the question is how to set vif-locking-mode=locked to prevent IP spoofing while DVS Controller is active?!

I cannot find any infomation about this situation at oficial docs.

Thank you,

Sergey