special effect on the minimap?

I'm trying to make a soccer ums variant where the ball isn't always on the map all the time

(like when a unit goes near the ball, he 'hold's it and it disappears from the map until he throws it again..)

I used the special effect action to make an effect so you can tell which unit has the ball currently (does anyone have a list of special effects? because i am just using the default one which shows an exclamation mark) but I can't figure out how to show who has the ball on the minimap..

I considered changing the unit with the ball from a basic unit to a hero, but replacing a unit also deselects the unit for the player.
If i treid using the select action, it makes EVERY player select that unit so that doesn't work.

Once again, I post the crap of special effect list!
After the replaced action, use select (last replaced unit).

On the minimap the only special effect you can use is the exclamation mark. I don't see why this is a problem though -- map ping was the only minimap effect you had in SC too.