The auto-delete function does not work in Virtual Feeds. In the global settings I have it set to delete "All done episodes". Even when I change the feed options for the virtual feed from "Use global setting" to "All done episodes", it still doesn't delete episodes that are done.
This is by design (although it is confusing and inconsistent). For the vast majority of cases, people don't want to auto-delete virtual feeds since most people use it for audio book, which they don't want deleted when they're done. There were quite a few people that had the global setting to auto-delete, and were blowing away their virtual feeds so I exempted the virtual feeds from auto-delete.
I think what make sense here is to allow virtual feeds to auto-delete but only when the feed option for that feed (not the global) is enabled. This will prevent accidents but still support your case where you actually do want to delete virtual feed content.
I have an issue to do that here - http://mantis.snoggdoggler.com/view.php?id=1051
Thanks for the feedback.