How to modify tooltip in gmap module?

I would like to modify tooltip (info window that p开发者_开发问答ops up when you click on a marker). I'm trying to embed a text field and submit button on the tooltip, like in this example http://econym.org.uk/gmap/example_map4.htm.

In template.php, you can modify the output of the gmap field. Of particular interest to you is the var $gmaptext

function salive_preprocess_node(&$vars, $hook) {
  $vars['gmap'] = salive_render_gmap($vars['node']);
}

/**
 * Render a google map from a node object from a venue content type
 *
 * $node is an object, and should have the location fields, like venue content type does.
 */
 function salive_render_gmap($node) {
  $location = $node->location;
    $gmaptext = 
    $location['name'] . '<br />' .
    $location['street'];
    if (isset($location['additional'])) {
      $gmaptext .= $location['additional'] . '<br />';
    }
    $gmaptext .= $location['city'] . ', ' . $location['province'] . ' ' . $location['postal_code'] . '<br />';
    if (isset($location['phone'])) {
      $gmaptext .= $location['phone'];
    }
    if (isset($field_website[0]['safe'])) {
      $gmaptext .= '<br /><a href="' . $field_website[0]['safe'] . '" target="_blank" rel="nofollow">Web site</a>';
    }

    $map_array = array (
        'id' => $node->id,         // id attribute for the map
        'width' => "580px",        // map width in pixels or %
        'height' => "400px",      // map height in pixels
        'latitude' => $location['latitude'],    // map center latitude
        'longitude' => $location['longitude'],  // map center longitude
        'zoom' => 15,              // zoom level
        'maptype' => "Map",       // baselayer type
        'controltype' => "Small",  // size of map controls
        'markers' => array(
            array(
                'text' =>  $gmaptext,
                'longitude' => $location['longitude'],
                'latitude' => $location['latitude'],
                'markername' => 'big red'
            )
      )
    );
    if (count($map_array) < 2) {
      drupal_set_message('$map_array was empty');
      if (module_exists('devel')) {
        dpm($map_array);
      }
    }
    else {
      return (theme('gmap', array('#settings' => $map_array)));
    }
}

Then, in page.tpl.php:

<?php
if ($gmap):
  print $gmap;
endif;
?>