>> I found the solution might be:
>>
>> MAPersonModel>>description
>>         ^super description copy;
>>                 add: CustomDescription ;
>>                 yourself
>>
uhm it looks like an error I made ;) ...

MAPersonModel>>description
        ^super description copy       (<-  without  #;  otherwise it 
will add over and over descriptions)
                add: CustomDescription ;
                yourself

and I used addAll: too

see you

Cédrick