Is there any way to create new category affinity parameters? If there is, how can a create a new one?

I am starting with Adobe Target and I would like to understand some weird things I see playing with the profile scripts.I am creating and storing a simple list of objects containing. the objects contains just two attributes: one is an string and the other one is an integer.When I try to get this back from the user parameter the first thing that I see is that the Json is not in a Json format anymore as it changes the ":" with "=", the other thing I see is that the integers has been converted into...