Hi,
I wrote an abstraction, using "pd-messages" to create objects, [index] to store their ID, and" mouse cut" method to delete them with an ID : http://abel.jerome.free.fr/pd/dynamic-patching/patchs/dyn-objects/dynObjects...
For more informations, I wrote some lines about dynamic patching here : http://abel.jerome.free.fr/pd/dynamic-patching/reviews/
Jérôme