Use of negative integers as primary keys

[rpalacpac]

I use random number primary keys that range from -999999 to 999999 in my Fabrik lists. This was based on an earlier database design using MS Access. Whenever I edit/view a list item/record that contains a positive primary key, I can edit/view it in a form with no problem. But when I edit/view a list item/record with a negative primary key, I get the error "We are unable to find this record".

I have looked into the models\form.php code but it is quite complicated. Is there a way for Fabrik to use a negative primary key to edit/view a form?