Can't transmog my chest/legs

[Karmen]

I want to transmog my chest " Vengeful Gladiator's Silk Rainment " with " Crimson Silk Vest "
and my legs " Vengeful Gladiator's Silk Trousers " with " Crimson Silk Pantaloons " , but i can't , it doesn't show in the chest/legs menu..

[Henhouse]

Looks like these items are white (Common) quality which would be why. Judging by the WoWHead comments, they did not become uncommon (Green) until Wrath.