Retrieving data extension used to filter e-mail send

I'm new to ExactTarget, and I'm having some hard time to do something that should be simple.

We direct our e-mails using a list of All Subscribers, and filter then using data extensions. When I go on the tracking page of a particular e-mail, there it is in the Summary, all the info and the Data Extensions, on the format:

name (number) sent (Using All Subscribers) (number sent)

The thing is, when I do a tracking extract I don't get this information. I tried to extract everything that was possible, and couldn't get this information. All I get is, for each sendID (for each subscriber in fact), the ListID, which will always be the same (the one for All Subscribers). I want to know which segment we used.

Tried to deep dive on the SOAP API, with no luck, again all I can retrieve is the List, never the data extension.

This must be retrievable, once it is on the Tracking Summary. So my question is how do I retrieve is.

I considered programming a simple robot to scrape for this info, but there must be a better way.

Thanks

Guess nobody cares much, but in case someone faces the same problem, I've got a final answer for support, the information is not retrievable (except through the tracking summary, which must be accessed one by one) through API or UI

But a custom report can be asked for. Still waiting to see if it's free of charge (should be, right? As it's something that should be available in first place)