gistfile1.xml

<new_text_field name="name" label="Name: " icon="user.png">
    <validation>
         <required>Please, enter a name.</required>
     </validation>
 </new_text_field>

<new_radio_list name="subject" label="Subject: ">
    <options>
        <option>General</option>
        <option>Sales</option>
        <option>Complain</option>
    </options>
    <validation>
        <required>Please, choose a subject.</required>
    </validation>
</new_radio_list>