Load Joomla Text Editor for custom field

Hi.

I've made a custom filed - textarea for products. The problem is that it doesn't keep text formating and I need a text editor, but I can't figure it out how to load it. For product description I use JCE Editor, but I don't know how to use it for my custom textarea.

My custom filed is:

<textarea name="product_fragment" cols="80" rows="10"><?php echo $product_fragment; ?></textarea>

Joomla 2.5/AyelShop/OpenCart 1.5.1.3