RoC units in TFT?

I've been wanting to use the siege engine in one of my maps, but all there is, is the siege engine. Is there a way to use RoC units in TFT?

use the old models.

Units\Human\SteamTank\SteamTank.mdx (is that a real model?)

Somethin like that

Right under the model selection box there is a version selection box. Try unselecting all of them and selecting only RoC. If those fail, just go into the model choosing area and take off the _V1 after the model path.

All you have to do is go into the object editor and set the unit you want to have the steam tank model to have the siege engine model. Then you have to say ok then reclick the model thing and were it says the models path you have to change it to that of a steam tank.
Here is a step by step tutorial:

The option Myster Mystery suggested is, in my opinion, the easiest and simpliest way to go about it.

It works on all units that changed by TFT, including the Steam Tank, Ballista, Catapult, the Priest, and the Sorceress. It however, naturally, won't change back units who changed in other ways due to TFT, like the Wyvern. But that's easy to remedy.