Include Grid in edit template

[Guillaume]

Hi, my grid has a costum popup edit template where I want to be able to manage a list of subitems. I thought I would use another grid inside the edit tempate but I get an error "Invalid Template". Is it supported to have another grid inside an edit template of a parent grid? If so could I get an example of how to acheive it?
Thanks
Guillaume

My template looks like this:

<script id="popup_editor" type="text/x-kendo-template">
   <div class="k-edit-label">
    <label for="Title">Title</label>
   </div>
            <input type="text" class="k-input k-textbox" name="Title" data-bind="value:Title">

   <div class="k-edit-label">
    <label for="ExpiryDate">Expiry Date</label>
   </div>
   <input type="text"
    name="ExpiryDate"
    data-type="date"
    data-bind="value:ExpiryDate"
    data-role="datepicker" />

            <div id="subitemsGrid"></div>
            $("#subitemsGrid").kendoGrid(##removed code to get list of subitems in grid##);
  </script>