Change Team Color

Only to be sure ...
I want players to be able to build towers with a chosen team color, and not with their ones.
For example, I want player1, red, to build the basic Guard-tower in blue (the blue from player2; no imported color!).
It works quite fine if I creat the towers already in the WE, but in game everytime I try to build a tower with a worker, the tower always appears in the players team color!?

I set the attribute "art - team color" to "blue" and
I set the attribute "art - allow own teamcolor" to "true"

So, did I forget to change another attribute or is this just don't working what I'm trying?

This code will work for changing team color:

Unit - Give Ownership of <your tower> to <player X> changing team color (player x is the player that has the team color you want)
Unit - Give Ownership of <your tower> to <original owner> retaining team color (gives it back again)

Problems i see: this will reveal the map for the other temporary owner.
You can therefore do a check if the point is visible for this temp owner and if no, then create a temporary visibility modifier there that ensures it's not going to be revealed or something similar.

But my main question:
Does it also work with only editing a unit in the object editor?
Or do I have to use triggers?

Thanx for reply PitzerMike,
I already thought of something like this, with triggers.
The reveal of the map is no problem, I can give the unit a computer for short.
But also thx 4 added additional explanation how to solve even this!

O.k., doesn't matter.
I used triggers and there I also found a command in normal GUI that says, that you can change the color even without having to change the owner!
So I used this.