Hi,
I made a quick fix to add the WordPress "media library" button next to the Podcast "Media URL" field.
That way, Wordpess media "pop-up" can be used to select a mp3 file present in the media library or upload and select a new one.
Just patch the following file :
wp-content/plugins/powerpress/powerpressadmin-metabox.php
[Code moderated as per the Forum Rules. Please use the pastebin]
