Vengeful shoulder transmog for Death Knight

Hello, i've seen some Death Knights in Frostmourne Realm transmog their shoulder piece into "Vengeful Gladiator's Lamellar Shoulders" which is the vengeful set of Paladin.
I guess it's because DK doesn't have a vengeful set so they adapted the paladin ones.
I have some questions about this:

1) If i get the token from BT where is the NPC to exchange it?

2) Can i exchange the Vengeful shoulder with honor as well, without the token?

3) This exchange will be still possible with next patches (ToC and ICC)?

4) Is this doable in Icecrown Realm?

Thanks.