wordpress plugin mailjet-for-wordpress can not insert contact properties field to newsletter form in frontend

I use plugin mailjet-for-wordpress.

What I want

want user to input thier nom,prenom and email in front end like this :http://gyazo.com/b58675c671584f8edc6ab6d703370ba9

My problem

for field I just add like nom,prenom it does not show in my admin page the same as email field when user subcribe : http://gyazo.com/9b72fdc03d22732cf21ddac9f70b2c33

what i have tried

I have tried to create contact properties field in mailjet like nom,prenom. And I’m also try to modify widget “Subscript to our newsletter” I add more fields in the newsletter form. I have modify code as below :

file mailjet-widget.php

    // WIDGET CODE GOES HERE
    echo '
    <form class="subscribe-form">
        //add field nom
        <input type="text" name="nom" placeholder="' . __('Nom', 'wp-mailjet') . '" class="username">

        //add field prenom
        <input type="text" name="prenom" placeholder="' . __('Prenom', 'wp-mailjet') . '" class="username">
        //email it is original field in default newsletter mailjet form
        <input id="email" name="email" value="" type="email" placeholder="' . __('your@email.com', 'wp-mailjet') . '" />

        <input name="action" type="hidden" value="mailjet_subscribe_ajax_hook" />
        <input name="list_id" type="hidden" value="' . $list_id . '" />
        <input name="submit" type="submit" class="mailjet-subscribe" value="' . __($button_text) . '">
    </form>
    <div class="response">
    </div>';

And also in this function mailjet_subscribe_from_widget()

public function mailjet_subscribe_from_widget()
{
    // Get some variables - email, list_id, etc.
    $email = $_POST['email'];
    $list_id = $_POST['list_id'];
    //field add
    $nom = $_POST['nom'];
    $prenom = $_POST['prenom'];

    // Add the contact to the contact list
    $result = $this->api->addContact(array(
        'Email'     => $email,
        'Nom'       => $nom,
        'Prenom'    => $prenom,
        'ListID'    => $list_id
    ));

    // Check what is the response and display proper message
    if(isset($result->Status)) {
        if($result->Status == 'DUPLICATE'){
            echo '<p class="error">';
            echo sprintf(__("The contact %s is already subscribed", 'wp-mailjet'), $email);
            echo '</p>';
            die();
        }
        else if($result->Status == 'ERROR'){
            echo '<p class="error">';
            echo sprintf(__("Sorry %s we couldn't subscribe at this time", 'wp-mailjet'), $email);
            echo '</p>';
            die();
        }           
    }

    // Adding was successful
    echo '<p class="success">';
    echo sprintf(__("Thanks for subscribing with %s", 'wp-mailjet'), $email);
    echo '</p>';
    die();
}

I have tried to search and test like this for a few days but still can not get the result.I am new with the plugin mailjet-for-wordpress plugin,
Do anyone know help me to find the solution please,

Thanks in advanced,