how to add a row to grid

[hicker]

hi
i'm using 1.0 alpha 3 and get records with xml

codes_ds = new Ext.data.Store({
proxy: new Ext.data.HttpProxy({url: 'katalogcodes.php'}),
reader: new Ext.data.XmlReader({
root: 'results',
record: 'item',
totalProperty: 'totalCount',
id: 'id'
},
[
'id','code_type','code'
])
});

i couldn't find how to add a row manually...