<?xml version="1.0" encoding="utf-8"?>
<form>
    <fieldset name="general" addfieldpath="administrator/components/com_convertforms/models/forms/fields">
        <field name="match" type="comparator"/>
        <field name="value" type="campaigns" 
            label="NR_CONVERTFORMS_LIST" 
            description="NR_CONVERTFORMS_LIST_DESC"
            multiple="true"
        />
    </fieldset>
</form>