I try to add new method and new property to a form. Can anyone tell me how to add a array property? example: r_aoaddmodedisabled[20,0]

When you name the property, name it as you would declare an array, just like you have it above, except that you cannot have 0 columns.
e.g.,

r_aoaddmodedisabled(20,1)

Or you can do the following from the command window

ASELOBJ(laForm,1)
laForm[1].AddProperty("r_aoaddmodedisabled(20,1)")