To my knowledge, Easy populate does not give you Custom Product Fields. But if you have coded them and added them yourself, you can make easy populate recognize them by adding them in the configuration for easy populate under admin, where you see the custom products field. For example, if you have created the field SKU, then if you enter in the configuration file, easy populate will add a column for that when it creates your CVS file.

So are you looking to create a custom field?