There is a Podlove episode slug bug that prevents the use of the WP media uploads as episode assets.
Steps to reproduce:
1. Set podlove base URL to http://mysite.com/wp-content/uploads/sites/4/ (or whatever)
2. Upload a media file and note it's File URL, such as path, such as http://mysite.com/wp-content/uploads/sites/4/2013/06/003/mp3
3. Create an episode. Input the slug, i.e. 2013/06/003
4. Click the 'MP3' asset type. Podlove will verify that the media exists. Success.
5. Publish the episode and browse to it.
6. Observe that Podlove has converted the episode slug to 2013-06-03.mp3, removing the slashes.
7. Confirm this from the main Podlove dashboard. The podlove dashboard says the episode assets are not found, but the podlove episode editor says that they are found.
To me, the correct fix is to not convert / into -. Otherwise there is no way to use the media folder to host episodes.