.Net Web Service with Ext data store

After using Ajaxpro with a couple of applications, I thought I should look into a more standardized approach for Ext/.Net integration. Specifically, how to bind SQL data on the server to a Ext data store. Ajaxpro's future seems uncertain.

First the Web Service:

[WebMethod]
public XmlDocument getSites(String Site, String Type, String Disc, String Manu, String query, String limit, String start, String callback)
{

XmlDocument xmlDoc = new XmlDocument();
DataSet ds = new DataSet();
String sql = " Select SITE as col1 from mytable where site = " + Site;

// create a connection
SqlDataAdapter oda = new SqlDataAdapter(sql, connStringSQL);
oda.Fill(ds);
xmlDoc.LoadXml(ds.GetXml());
return xmlDoc;
}

And the Ext code, with the .Net xml doc having 'Table' as record:

// parameters that get passed
var inparms ={query: '', start: '', limit: '', callback: '', Site: '', Type: '', Disc: '', Manu: ''};

var xmlread = new Ext.data.XmlReader({ record: 'Table' }, [
// set up the fields mapping into the xml doc
{name: 'col1'} ]);

// create the Data Store
var dsSites = new Ext.data.Store({
// load using HTTP
proxy: new Ext.data.HttpProxy({method:'POST',url: 'Service.asmx/getSites'}),
reader: xmlread, params: inparms });
.
.
.
dsSites.load( { params : inparms});
or
dsSites.load( {params : {query: '', start: '', limit: '', callback: '', Site: 'London', Type: '', Disc: '', Manu: ''});