Mapping fields json request in drupalgap (unlimited fields value)

I spent a lot of time, but I can not understand
The drupalgap generates this json code for unlimited fields
field_tip_obiavlenia1":{"und":{"value":["1","2",""]}}}
But the correct query should look like this.
field_tip_obiavlenia1":{"und":[{"value":"1"},{"value":"2"}]}
How can i use hook_assemble_form_value_into_field that send the correct json request