How to implement a C++ interface in blueprints?

Hi all!

I have this code:

/**
 * 
 */
UINTERFACE()
class ULiving : public UInterface
{
	GENERATED_UINTERFACE_BODY()
};

class ILiving
{
    GENERATED_IINTERFACE_BODY()

public:
    // Heals this actor
    UFUNCTION(BlueprintNativeEvent, BlueprintCallable, Category = "Living Actor")
    void Heal(float amount, bool force);
};

And the idea is that my actor implements it, but when i add it to my actor’s interfaces, i don’t get any red event node to implement (if i create a blueprint interface i do get that node in the “Add event” category).

With this code, what i exactly obtain, is two nodes, one of them named “Heal (Message)”, with an envelope icon, and another identical node, but without any icon and named “Call to unknown function”.

What i’m doing wrong? :S.

See ya!