How to integrate a matlab class in a simulink block?

Hello everyone,

In Matlab 2013a, I developed a matlab class named as MyUnitDelay, it has properties "IC,u,y" and methods "initialize,step,update".

classdef MyUnitDelay < handle  
    properties
        IC; %initial condition
        u; %input port
        y; %output port
    end    
    methods
        function  initialize(obj,ic)
            obj.IC = ic;
            obj.u = 0;
            obj.y = 0;            
        end
        function  y = step(obj,u)
            obj.u = u;
            obj.y = obj.IC;
            y = obj.IC;            
        end
        function  obj = update(obj)           
            obj.IC = obj.u;
        end        
    end    
end

I want to create a special Simulink block in which I can create an instance of that class and call appropriate method according to simulation phase.

In this manner;

• What is the most appropriate Simulink block? Level-2 Matlab SFunction/Matlab Function/anything else?I can not use "Matlab System" block since Matlab 2013a version does not support that block.
• Should i derive the class from another superclass according to the block selection? If yes, what should be the superclass?
• I need to generate code from that model. Therefore i need a Simulink block which is supported by Simulink Coder.