I'd like to add a hook to a Magento core action (in this specific case Mage_Adminhtml_Sales_Order_CreateController::saveAction() but I hope there's a general solution).
Just a hunch, but it seems to me that there should be a way to add a hook to an action using Magento's XML, without having to override a class just to add a one-line Mage::dispatchEvent(). Perhaps this is wishful thinking.
Is there any way to do this using XML? Or no? If so, how?