Best How To :

The fastest way to do what you are looking for is overriding the edit template. At your admin serivce declaration you can do so:

services:
    sonata.admin.mail:
        class: %sonata.admin.category.class%
        tags:
            - { name: sonata.admin, manager_type: orm, group: "Categories", label: "Category" }
        arguments:
            - ~
            - %skooli.category.class%
            - ~
        calls:
            - [ setTemplate, ["edit", "AcmeAdminBundle:CategoryAdmin:edit.html.twig"] ]

Then, under AcmeBundle/Resources/views/CategoryAdmin/edit.html.twig you can have something like this:

{% extends 'SonataAdminBundle:CRUD:base_edit.html.twig' %}
{# Override any block from the parent view if necessary #}
{% block products %}
    <ul>
    {% for product in object.products%}
        <li>{{ product.name }}</li>
    {% endfor %}
    </ul>
{% endblock products %}