EDIT

    $items[] = array(

      // usage: url('cdm_api/proxy/'.urlencode($content_url)."/$theme");

      'path' => 'cdm_api/setvalue/session',

      'callback' => 'setvalue_session',

      'access' => true,

      'type' => MENU_CALLBACK,

    );

function setvalue_session(){

  if(strlen(arg(3)) > 0){

    $keys = explode('|', arg(3));

  }

  $val = arg(4);

  // prevent from malicous tags  

  $val = strip_tags($val);

  $var = &$_SESSION;

  $i = 0;

  foreach($keys as $key){

    $hasMoreKeys = ++$i < count($var);

    if($hasMoreKeys && (!isset($var[$key]) || !is_array($var[$key]))){

      $var[$key] = array();

    }

    $var = &$var[$key];

  }

  $var = $val;

}

.media ul.primary li a

, .media ul.primary li.active a

, .media ul.primary li a:hover

, .media ul.primary li a:visited

, .media ul.secondary li a

, .media ul.secondary li.active a

, .media ul.secondary li a:hover

 , .media ul.secondary li a:visited{

	margin-left : 0px;

}

.media ul.primary li a.active{

  font-weight: bold;

}

    // expected callback arguments: media_uuid, mediarepresentation_uuid, part_uuid or part#

function cdm_dataportal_view_media($mediaUuid, $mediarepresentation_uuid = false, $part = 0){

   return theme('cdm_media_page', $media, $mediarepresentation_uuid, $part);

function path_to_media($uuid, $representaion_uuid = false, $partId = false){

  $out = 'cdm_dataportal/media/'.$uuid;

  if($representaion_uuid){

    $out .= '/'.$representaion_uuid;

    if($partId !== false){

      $out .= '/'.$partId;

    }

  }

  return $out;

function theme_cdm_media_page($media, $mediarepresentation_uuid = false, $partId = false){

  // determine which reprresentation and which part to show

  $representationIdx = 0;

  if($mediarepresentation_uuid){

    $i = 0;

    foreach($media->representations as $representation) {

      if($representation->uuid == $mediarepresentation_uuid){  

        $representationIdx = $i;

      }

      $i++;

    }

  } else {

    $mediarepresentation_uuid = $media->representations[0]->uuid;

  }

  $partIdx  = 0;

  if(!is_numeric($partId)){

    // assuming it is an uuid

    $i = 0;

    foreach($media->representations[$representationIdx]->parts as $part) {

      if($part->uuid == $partId){  

        $partIdx = $i;

      }

      $i++;

    }

  } else {

   // assuming it is an index

    $partIdx = $partId;

  }

  //$out .= theme('cdm_media_gallerie_image', $representation->parts[$partIdx], $imageMaxExtend);

  $out .= theme('cdm_openlayers_image', $media->representations[$representationIdx]->parts[$partIdx], $imageMaxExtend);

  $out .= '</ul>';

  //tabs for the different representations

  //ul.secondary 

  $out .= '<ul class="primary">';

  foreach($media->representations as $representation){

    $out .= '<li>'.l($media->representations[$representationIdx]->mimeType, path_to_media($media->uuid, $mediarepresentation_uuid, $partIdx)).'</li>';

  }

  $out .= '</ul>';

  //$out .= '<tr><th colspan="3">'.t('MimeType').': '.$media->representations[$representationIdx]->mimeType.'</th></tr>';

  $i = 0;

  foreach($media->representations[$representationIdx]->parts as $part){

    $out .= '<tr><th>'.t('Part').' '.($i + 1).'</th><td>';

    $out .= '</td><td><a href="'.url(path_to_media($media->uuid, $mediarepresentation_uuid, $i)).'">'.theme('cdm_media_gallerie_image', $part, $thumbnailMaxExtend, true);'</a></td><tr>';

    $i++;

 var layerOptions = {

     maxExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

     isBaseLayer: false,

     displayInLayerSwitcher: false

  };

    {layers:"topp:tdwg_level_1",transparent:"true", format:"image/png"},

    layerOptions

    {layers:"topp:tdwg_level_2",transparent:"true", format:"image/png"},

    layerOptions

    {layers:"topp:tdwg_level_3", transparent:"true", format:"image/png"},

    layerOptions

    {layers:"topp:tdwg_level_4",transparent:"true", format:"image/png"},

    layerOptions

 // make baselayer

 layerOptions[\'isBaseLayer\'] = true; 

    layerOptions

   var mapOptions={

       maxExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

       maxResolution: '.(360 / $display_width).',

       restrictedExtent: new OpenLayers.Bounds(-180, -90, 180, 90),

   map = new OpenLayers.Map(\'openlayers_map\', mapOptions);

   '.$add_tdwg1.'

   '.$add_tdwg2.'

   '.$add_tdwg3.'

   '.$add_tdwg4.'

   map.zoomToMaxExtent();

  $renderPath = 'related_taxon';

  $nameHtml = theme('cdm_taxonName', $taxon->name, $taxonUri, $referenceUri, $renderPath);

  $showThumbnails = $_SESSION['pageoptions']['searchtaxa']['showThumbnails'];

  if( !is_numeric($showThumbnails)){

    $showThumbnails = 1;

  }

  $setSessionUri = url('cdm_api/setvalue/session').'/pageoptions|searchtaxa|showThumbnails/';

  drupal_add_js('$(document).ready(function() {

        // init

        if('.$showThumbnails.' == 1){

              $(\'.media_gallery\').show(20);

        } else {

          $(\'.media_gallery\').hide(20);

        }

        // add change hander

        $(\'#showThumbnails\').change(

          function(event){

            var state = 0;

            if($(this).is(\':checked\')){

              $(\'.media_gallery\').show(20);

              state = 1;

            } else {

              $(\'.media_gallery\').hide(20);

            }

            // store state in session variable

            var uri = \''.$setSessionUri.'\' + state;

            jQuery.get(uri);

          });

        });', "inline");

  $out = '<div class="page_options"><form name="pageoptions"><input id="showThumbnails" type="checkbox" name="showThumbnails" '.($showThumbnails == 1? 'checked="checked"': '').'> '.t('Show Thumbnails').'</form></div>';

          $(\'div.'.$verticalSroller.'\').scrollTo($(\'.focused\'), 400, {over:-3});});

 * @deprecated replace by according taxonomictree function

 * TODO where does the stored UUID come from?