1) Create unit and into it's init field type: this addEventHandler ["HandleDamage",{if (_this select 1=="") then {damage (_this select 0)+((_this select 2)$#)}}]
where instead of "$" type "/" or "*" and instead of "#" type any number.
2) Run mission and shoot the unit with Handledamage command on and see that the damage system is wrong and that it doesn't care about Handledamage command.