Magento custom API for adding product wishlist

Magento custom API for adding product wishlist

I am implementing the magento custom API for wishlist.
Can anybody know, how to add the wishlist.
I tried using the magento 'wishlist' module, but the product is not saving
in to wishlist.
I am using the following function to save.
public function addNewItem($product, $customer_id, $buyRequest = null,
$forciblySetQty = false)
{
}