Retrieving the listbox values from a modelpopup partial view in asp.net mvc2 using fluent hibernate

Question

i am having tow list boxes in a modalpopup window. In the first listbox i am storing all the availble products.the other list box will be initially empty. using couple of buttons i can pass listitems between the listboxes. my problem is when i assign some listitems to the second listbox. i cannot get them back go the controller as a part of the viewmodel i am assigning.

Following is the piece of code that i tried to use. apart from the list boxes there are some other items in the viewmodel.

View

<tr>
        <td class="value" style="width: 45%; height: 75px">
            <%   var lst = new SelectList(Model.GetAllProducts, "ProductID", "ProductName").ToList();%>
            <%: Html.ListBox("FromBox", lst, new { style = "width: 85%" })%>
        </td>
        <td class="label" style="width: 5%; height: 75px">
            <input type="button" id="btnMoveRight" value=">>" onclick="fnMoveItems('FromBox','ToBox')" />
        </td>
        <td class="label" style="width: 5%; height: 75px">
            <input type="button" id="btnMoveLeft" value="<<" onclick="fnMoveItems('ToBox','FromBox')" />
        </td>
        <td class="value" style="width: 45%; height: 75px">
            <%   var lst1 = new SelectList(Model.GetAssignedProducts, "ProductID", "ProductName").ToList();%>
            <%: Html.ListBox("ToBox", lst1, new { style = "width: 85%" })%>
        </td>
    </tr>

in the Controller my viewmodel is like this

public class ProductsViewData
        {
            public Products Products { get; set; }
//            public string PrivID { get; set; }
            public List<Products> GetAllPriviliges { get; set; }
            public IList<Products> GetAssignedProducts { get; set; }
        }

and my create method in the controller is as follows

      [HttpGet]
            public ActionResult Create()
            {
                try
                {
                    WorkUnit workunit = new WorkUnit();
                    Products _Products = new Products();
                    var viewModel = new ProductsViewData { Products = _Products };
                    viewModel.GetAllProducts = _productsService.GetAll(workunit).ToList();
                    viewModel.GetAssignedProducts = _svcProductsProducts.GetProductProduct(0);// binds o items to the second list box





                    return PartialView("Create", viewModel);
                }
                catch (Exception e)
                {
                    TempData["StatusLine"] = "Error: " + e.Message;
                    return View();
                }
            }

            /// <summary>
            /// Add Product
            /// </summary>
            /// <returns></returns>
            [AcceptVerbs(HttpVerbs.Post)]
            public ActionResult Create(ProductsViewData ViewModel)
            {
                try
                {


                    WorkUnit workunit = new WorkUnit();
                    Products _Products = new Products();


                    _Products.EndDate = System.DateTime.Now;
                    _Products.StartDate = System.DateTime.Now;
                    _Products.CreatedDate = System.DateTime.Now;

   // when i try to look for the items  in the viewmodel i could not see any values for the getassignedproducts.

                    if (!TryUpdateModel(_Products, "Products"))
                    {
                        var viewModel = new ProductsViewData
                        {
                            Products = _Products
                        };
                        viewModel.GetAllProducts = _productsService.GetAll(workunit).ToList();
                        viewModel.GetAssignedProducts = _svcProductsProducts.GetProductProduct(0);

                        return View("Edit", viewModel);
                    }

                    //Save Product

                    _ProductsService.Save(workunit, ViewModel.Products);

                    TempData["StatusLine"] = "Added new Product ";

                    return RedirectToAction("List");
                }
                catch (Exception e)
                {
                    TempData["StatusLine"] = "Error: " + e.Message;
                    return View("Edit");
                }
            }

the problem i am having is i am not able to understand how to pass the list of the items in the "ToBox" (second List box) assigned from " FromBox" (first list box) back to the controller.

I am new to MVC2 and fluent nhibernate.

Please let me know if there is a way to do this.