$10

Nested set categories, related category items, sfDoctrineChoice

I'm using doctrine nested sets to manage a template category hierarchy, however I also need to get out the actual templates that are in those categories using the sfWidgetFormDoctrineChoice on the forms.

So, how would I go about creating a dropdown for the form that outputs the TemplateCategory and corresponding Templates, so that I can select templates to load? Ideally, template categories would not be selectable.

Here is what I want the resulting dropdown to look like:

TemplateCategoryRoot
-- Template 1
-- TemplateCategory1
---- Template 2
---- Template 3
-- Template Category2
----Template4
---- Template Subcategory1
------ Template 5

Template:

    columns:

        id:                     { type: integer(4), primary: true, autoincrement: true }

        name:                   { type: string(150) }

        content:             { type: clob(65532) }

        template_category_id:   { type: integer(4) }

    relations:

        TemplateCategory:   { local: template_category_id, foreign: id}



TemplateCategory:

    actAs:

        NestedSet:

            hasManyRoots: true, 

            rootColumnName: root_id

    columns:

        id:             { type: integer(4), primary: true, autoincrement: true }

        name:           { type: string(150) }

        is_public:      { type: boolean }