knockout.js - Update observed model in custom knockoutjs binding -

i'm trying integrate jquery autocomplete extension in foreach knockout loop. i've created custom binding , autocomplete works. after autocomplete need update observable item model , cannot figure out how it. here code:

<!-- ko foreach: items --> <input data-bind="autocomplete: { source: '/products/item-search-ajax', options: { delay: 100, max: 20, minchars: 2, extraparams: { itcode: 1 }}, findcallback: $parent.findvaluecallback }, value: partnumber" type="text"> <!-- /ko -->  <script type="text/javascript">          ko.bindinghandlers.autocomplete = {             init: function (element, valueaccessor, allbindings, viewmodel, bindingcontext) {                 var settings = valueaccessor();                 var source = settings.source;                 var options = settings.options;                 var findcallback = settings.findcallback;                 $(element).autocomplete(source, options);                 $(element).result(findcallback);                 ko.bindinghandlers.value.init(element, valueaccessor, allbindings);             },             update: function(element, valueaccessor) {                 var value = valueaccessor();                 ko.bindinghandlers.value.update(element,valueaccessor);             }          };          function quoteviewmodel() {             var self = this;              self.items = ko.observablearray(...);              self.findvaluecallback = function(event, data, formatted) {                  // need update item model here autocomplete             };         }   </script> 

you can pass $data (which in foreach item model) object function returns handler function such:

self.findvaluecallback = function(item) {     return function(event, data, formatted) {         //u have access particular item     } } 

and inside binding: findcallback: $parent.findvaluecallback($data)