Custom variables/fields for units? [closed]

Is there a way to associate new/custom variables with units?

There are two triggers I want to apply on a unit.

• First trigger, invoked on a unit, should check the current order assigned to it and remember the order target (of type unit or integer (unit ID))
• Second trigger occuring on the same unit should recall the value, and do something with it. But when the second trigger occurs, the old order does not exist anymore.

There is UnitSetCustomValue, but this one works on Real types and not int or unit. I cannot store unit-ID in it because I lose precision.