Sorry that this is so complicated. These are features that only a small group of PowerPress users use.
Try this: In PowerPress settings, turn off podcast type podcasting, turn on podcast channels and then click save. Then go into podcast channels, edit the default podcast channel, and go to the last tab "Other Settings". Find the option titled "Custom Post Type", select "All Post Types" then click save. What this will do is include all post types into your podcast only feed. It should work, but it has been a few months since I last tested this. BTW If post type podcasting is enabled, the "Custom Post Type" option in Podcast Channels is not available, because it would conflict with the post type podcasting feeds.