autocomplete suggestions not showing
===

I am trying to implement autocomplete with a webservice. Everything seems to return ok, but the autocomplete suggestions are not displayed under my field. Do I have to parse the return xml? All help is appreciated.

field
    <label for="kwSearch">Keyword</label>
    <input type="text" name="kwSearch" id="kwSearch" />                
    <button onclick="submitSearch('keyword','kwSearch');return false">Search</button>

Autosearch function

    $('#kwSearch').autocomplete(
        {
            source: function (event, ui) {
                var partial = event.term;

                $.ajax({
                    type: 'POST',
                    url: 'WebService.asmx/keywordLookup',
                    success: function (data) {
                        alert(data.responseText);
                    },
                    error: function (data) {
                        alert(data.responseText);
                    },
                    data: { partial: partial },
                    dataType: "xml"
                })
            }

        });

return text

    <?xml version="1.0" encoding="utf-8"?>
    <ArrayOfString xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://hworld.org/">
      <string>abortion</string>
      <string>abuse</string>
      <string>addiction</string>
      <string>addiction prevention</string>
      <string>adhd</string>
      <string>adoption</string>
    </ArrayOfString>