Help Modifying Existing Enfold Function by Using Child Theme

I need some guidance slightly modifying an existing function within Enfold by using my child theme’s functions.php file. Here is what I am trying to do:

In the “enfold\config-templatebuilder\avia-shortcodes\image.php” file I am trying to add the following line

__('Custom (add custom border)', 'avia_framework' ) =>'am-custom',

to this part of the popup_elements() function

array(
	"name" 	=> __("Image Styling", 'avia_framework' ),
	"desc" 	=> __("Chose a styling variaton", 'avia_framework' ),
	"id" 	=> "styling",
	"type" 	=> "select",
	"std" 	=> "",
	"subtype" => array(
		__('Default',  'avia_framework' ) 	=>'',
		__('Circle (image height and width must be equal)',  'avia_framework' ) 	=>'circle',
		<strong>__('Custom (add custom border)',  'avia_framework' ) 	=>'am-custom',</strong>
		__('No Styling (no border, no border radius etc)',  'avia_framework' ) =>'no-styling',
	)
),

I’m just not sure where to start or what to put in the child’s functions.php file. I am trying to stay away from editing any enfold files if possible.

Thanks as always!