I treat cavalry armed with carbines more like mounted infantry. I have them fire while mounted using the firing mounted modifiers (- 2d6) from their greatest range. With normal or ferocious units, this will cause them to follow the cav. Used properly, this will draw off the unit from the main attack, and increase the distance, if successful from the main body, pulling them away from their tribal commander, making them activate on their own.
I know the rules say mounted infantry must dismount to fight, but units like the Natal Native Police, Natal Carabiniers, and Frontier Light Horse used methods that can't fit in the normal rules. They acted as gadflies, to draw off units. They dismounted, fired at long range, quickly remounted and rode farther away, repeating this until the enemy unit was too far away to be dangerous, and would then ride away. A European unit can only perform 2 actions, so I simulate their methods by firing mounted and withdrawing, pulling the enemy with them.
The problem that will raise it's ugly head is that the enemy reaction happens as soon as they are fired on, so, if the NC fire and then move, the enemy will perform their reaction before the NC can move on their activation. They can be caught, and they will be in open order.
The NNP, NC and FLH were small units, so mine are only 4 - 8 figures. A very good roll will inflict 1 casualty. Since they are firing mounted mounted, I don't allow the all-powerful Volley Fire. If you are lucky, you can repeat this on the same enemy unit throughout the game. If you are not, they get caught and slaughtered. They have helped to win a Zulu game or two.
Working within the rules to find a "historical" result.
The only good zombie no longer moves.