Event Response - Ordered unit doesnt work on buildings?

[Chaos-Hunter]

I have a TD were I wan't all my towers to be avaible to turn, but to make them turn they need atleast 1 movmentspeed as defult.
Therefor I added a trigger thats sets ther movmentspeed to 0 when they are constructed. The problem is that thy can still be ordered to move...
So I thought that if I tell them when they are ordered to target a point I order them to hold position, but it doesn't seems to work. I've tryed this before on common units and it works, but not when the units are buildings.
Here is the code:

    Events
        Unit - A unit Is issued an order targeting a point
    Conditions
        ((Ordered unit) is in ShortRangers) Equal to True
    Actions
        Unit - Order (Ordered unit) to Hold Position
        Game - Display to (All players) the text: dxgf

Are there anything wrong in the code, or is there a way around this? plz help.

Edit:
the game text message is not nessesary, I just used it to see if the events and conditions works, and it did.