Kentico 8.2 Registering custom macro methods - not working

Hi to all,

I'm exploring the creation of custom macro. I've been following the steps and samples here:

https://docs.kentico.com/display/K82/Registering+custom+macro+methods

but "ConnectStrings" is always missing and not available in the macro editor.

Please enlighten me if I missed something.

using System;

using CMS;
using CMS.MacroEngine;
using CMS.Helpers;


// Makes all methods in the 'CustomMacroMethods' container class available for string objects
[assembly: RegisterExtension(typeof(CustomMacroMethods), typeof(string))]
// Registers methods from the 'CustomMacroMethods' container into the "String" macro namespace
[assembly: RegisterExtension(typeof(CustomMacroMethods), typeof(StringNamespace))]
public class CustomMacroMethods : MacroMethodContainer {
    [MacroMethod(typeof(string), "Combines two strings, or appends a culture suffix when called with one parameter.", 1)]
    [MacroMethodParam(0, "param1", typeof(string), "First part of the string.")]
    [MacroMethodParam(1, "param2", typeof(string), "Second part of the string (optional).")]
    public static object ConnectStrings(EvaluationContext context, params object[] parameters) {
        // Branches according to the number of the method's parameters
        switch (parameters.Length) {
            case 1:
                // Overload with one parameter
                return ValidationHelper.GetString(parameters[0], "") + " - Resolved in culture: " + context.Culture;

            case 2:
                // Overload with two parameters
                return ValidationHelper.GetString(parameters[0], "") + " - " + ValidationHelper.GetString(parameters[1], "");

            default:
                // No other overloads are supported
                throw new NotSupportedException();
        }
    }