How to display category custom design layout in product view page?

Question

Let\'s say I have two categegories, A and B.

I set A to use \'layout_a\' on Catalog -> Catalog Categories -> Click a category -> click custom design tab

I se

Answer 1

I found the answer by myself.

1. Open product controller located in /app/code/Mage/Catalog/controllers/ProductController.php

2. add the following code into _initProductLayout method

   $update->addHandle('CATEGORY_'.$product->getCategoryId());

3. Open catalog layout xml located in /app/design/frontend/default/default/layout/catalog.xml

4. add