As I understand it, you want to populate a property in your model through Jquery.
If this is really the case, you can put a Hidden input in the view representing your model, and change the value of it through JQuery. If the element already exists (not being a hidden one), just grab the HTML element and change its value. MVC performs model binding to send the model to its controller via the elements name.
For example:
@model Meu.Model.FooModel
@using (Html.BeginForm())
{
@Html.HiddenFor(e => e.Atributo, new { id = "AtributoDoModel" })
<input type="submit" val="Enviar" />
}
<script>
$(document).ready(function(){
$("#AtributoDoModel").val("NovoValorDoMeuAtributo");
});
</script>
The above code should change the Attribute property of the FooModel model to the value "NewMySourceType" as per JQuery script.