Upgrading custom units

I have been creating my own race and i have tried to make the custom units be able to upgrade their attack and armor but instead of upgrading them and making them stronger it just changes the number that shows how many times they have been upgraded leaving their attack and armor the same. can some one tell me how this is done.

I am Making my own race too and I need the same answer.

By the way, I am doing a Murloc Race MOD called Rising of the Tide. What race are you doing?

my suggestion is use triggers. make it so once they upgrade change a variable and when the vairable is a certain number have it replace the units. thats the only way i can think of.

Are you just adding the upgrade to the list of upgrades that affect Murlocs or did you actually change the number that tells how much of a benefit they get as well. For example Grunts, Raiders, etc. are all affects by the melee upgrades but each unit also has a number that tells how much to add to their attack for each upgrade, this allows a powerful melee unit to get more benefit than a weaker one. For creeps this field will be set to 0, it actually not be there at all but then I don't know what you can do until someone figures out how to change the fields themselves.