parms in request object not being properly communicated url for next mashup

I have a custom mashlet that contains a grid.  When a grid row is clicked a value is obtained from the gird and should be passed to a new mashup.  However when this is run, while the value from the first grid is correctly extracted, the value is not correctly passed to the called mashup and the default value is displayed.

The correct value is 7, while the firebug console shows me a value of 253D5.

The relevant java script is shown below along with fire bug output

                var record = this.feedStore.getAt(rowIndex);
                        var BioID = record.get("BioID");
                        console.log("InListener: ",BioID);   
                        this.resultsDiv.innerHTML = "";
                        var resultStore = new Presto.extjs.ServiceStore({
                            connection: conn,
                            request: {
                                sid: "WatchListSighting1",
                                oid: 'Invoke',
                                //BioID%253D5
                                parms:[BioID],
                                //parms:[{"BioID": BioID}],
                                header: {resultFormat:'xml'}
                            },
                            remotePaging: false,
                            record: "/xml/sighting",
                            columns: ['BioID', 'SubjName','Location',{name: 'WhenSeen',type:'date'},'Lat','Lon'],
                            recordId: "BioID",
                            pageLimit: 10
                        });

data = {"sid":"WatchListSighting1","appId":"","oid":"Invoke","svcVersion":"","header":{"map":{"serviceHeader":{"map":{"serviceURL":"http:\/\/rmivatbiosoa:8080\/presto\/edge\/api\/rest\/WatchListSighting1\/Invoke?presto_user=$session\/username&presto_password=$session\/password&BioID%253D5"}}}}