jquery Autocomplete through WCF data service

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OData

WCFServices

jQuery-UI

<script type="text/javascript">
    $(document).ready(function () {
        var qry = "Db.svc/CustTypes?select=CustTypeTitle&$format=json";
        $('#Makes').autocomplete({
            source: qry
        });
    });
</script>

1. I'm unable to extract single column from odata service. above code still shows all the columns in CustType table.

2. How to bind it to autocomplete jquery UI to show only related records.