Adding a UObject based class to an array

So im trying to add in the editor an object to an array.
Its declared like that

UPROPERTY(BlueprintReadWrite, EditAnywhere, Category = "Units")
        TArray<UCodeUnit *> Units;

But when i try to add it to that array of mine, there is nothing there http://imgur.com/0PHlXi2
Am i missing something? Is it even possible? Or do i have to use TSubclassOf and create those objects on begin play?

Is your UCodeUnit class tagged with: UCLASS(Blueprintable) ?

I had this problem yesterday and adding UCLASS(Blueprintable) on the line above the UObject derived class declaration made it visible to be used in the editor.