Problem about filter in a column grid of combo type

I’m using a grid of three columns. One of these columns has the type combo.
We have positionned a filter “#select_filter”, on this column.
When we select the filter we have a list of numbers whereas we expect a list of caracters.
In fact the value is loaded not the data( if we use the text_filter, the filter is style based on the numeric value).
Is there a way to get in the filter the data and not the value ?

Here is the type of the data loaded by the combo in my grid:

...

Here is the code of the grid:
actionsGrid = new dhtmlXGridObject(‘actions_container’);
actionsGrid.setImagePath(folderimagename);
actionsGrid.setHeader(“Id, Utilisateur, Groupe”);
actionsGrid.setColumnIds(“id, utilisateur,groupe”);
actionsGrid.attachHeader(“#text_filter,#select_filter,#select_filter”);
actionsGrid.setInitWidths(“200,,”);
actionsGrid.setColAlign(“left,left,left”);
actionsGrid.setColSorting(“str,str,str”);
actionsGrid.setColTypes(“ro,combo,coro”);

<?php foreach($groupes->TableauData as $index=>$valeur) { echo 'actionsGrid.getCombo(2).put(' . $valeur['id_groupe'] . ','. '"'.$valeur['libelle_groupe'] . '");'; } ?>

actionsGrid.setSkin(“light”);
actionsGrid.enableColumnMove(false);
actionsGrid.enableColumnAutoSize(true);
actionsGrid.enablePaging(true, 20, null, “pagingArea”, true, “recinfoArea”);
actionsGrid.setPagingSkin(“toolbar”);
actionsGrid.init();

//Combo
var combo = actionsGrid.getColumnCombo(1);
combo.enableFilteringMode(true);
combo.loadXML(fileldap);

actionsGrid.loadXML(filename);

Thanks in advance,