jqGrid empty searchoptions

I'm using a custom search button to perform a multiple search. Looking at firebug it seems that there are missing parameters in the request sent to the server

_search true
filters {"groupOp":"AND","rules":[{"field":"name","op":"bw","data":"A"}]}
nd  1307956101759
page    1
rows    20
searchField 
searchOper  
searchString

when I use the the default search button all the parameters are correctly valorized and the search returns the matching rows.

jQuery("#poi_grid").jqGrid({ 
    url:'php/retrieve_pois.php', 
    editurl:'php/edit_pois.php',
    datatype: "json", 
    colNames:['Name', 'Region', 'Type','Website','PDF','Lat','Lon'], 
    colModel:[ 
        {name:'name',index:'name', width:150, search:true, editable:true}, 
        {name:'region',index:'region', width:70, search:true, editable:true}, 
        {name:'type',index:'type', width:70, search:true, editable:true}, 
        {name:'website',index:'website', width:90,sortable:false,search:false, editable:true}, 
        {name:'pdf',index:'pdf', width:150,align:"right",sortable:false,search:false, editable:true}, 
        {name:'lat',index:'lat', width:60, sortable:false,search:false, editable:true}, 
        {name:'lon',index:'lon', width:60, sortable:false,search:false, editable:true},
    ], 
    pager:'#pager',
    rowNum:20, 
    rowList:[20,30,50], 
    sortname: 'name', 
    viewrecords: true, 
    sortorder: "asc",
    height:259,
    onSelectRow: function(id){
        if(id && id!==rowid){
            jQuery('#poi_grid').restoreRow(rowid);  //restore last grid row
            rowid=id;   //save current row ID so that when focus is gone it can be restored
        }
    }
}); 
//Pager
jQuery("#poi_grid").jqGrid('navGrid','#pager',
    {edit:false,add:false,del:false,search:false,refresh:false}
)
//Custom button开发者_StackOverflow中文版s
.navButtonAdd('#pager',{
    caption:"",
    title:"Search", 
    buttonicon:"ui-icon search", 
    onClickButton: function(){ 
        jQuery("#poi_grid").jqGrid('searchGrid', {
            sopt:['eq','ne','cn','bw','bn'],
            multipleSearch:true
        });
    }, 
    position:"last"
 });

I'm doing something wrong... but what? Thank you in advance!

---

I don't think that something are missing in the request with the exception of sidx=name and sord=asc which will be send but not included in your data.

Because you use multipleSearch:true option of the searchGrid all information about the searching parameters are encoded in the filters parameter corresponds to the documentation. The empty parameters "searchField=", "searchString=" and "searchOper=" used in case of multipleSearch:fasle should be just ignored.