RSS enclosures are a way of attaching multimedia content to RSS feeds by providing the URL of a file associated with an entry, such as an MP3 file to a music recommendation or a photo to a diary entry. (See "http://en.wikipedia.org/wiki/RSS_enclosure").

The mapping from SyndEntry to content node seems to be done in

info.magnolia.module.rssaggregator.importhandler.RSSFeedImportHandler.createFeedChannelEntryNode(SyndEntry, String, Content)

The method does not store any enclosures in the node. I suggest to extend it to store enclosures as well.