Automatic resource deallocation fails

Hello, I am trying to make use of automatic resource deallocation. Registering a destructor for a resource is no problem, doing zend_list_insert() zend_list_delete() will properly call the destructor. However, when I assign the resource value to a pval container and pass it back as return value from a function, as soon as all references to this pval container are lost (calling unset() on the variable, overwriting it with different values etc.), the destructor is not being called. Am I required to decrease the reference count manually somewhere? Till