Don't try it randomly. You're trying to call an action on a
block/product_new. So go into the class
Mage_Catalog_Block_Product_Abstract and see what function could do the job (double Ctrl+O in eclipse)
Here i see a
Mage_Catalog_Block_Product_Abstract::addColumnCountLayoutDepend($pageLayout, $columnCount) function.
Maybe it can help you. Example: