Allow for standard rss feed for document post type

The custom revision rss feed is great.  But I have a case where we just want to show the standard custom post type rss feed via the stardard wordpress rss feed:

/feed?post_type=document

I added a simple if statement to two functions that are messing this up: hijack_feed and revision_feed_auth.  Basically, I'd like to add a setting panel for wp document revisions and allow the user to choose the type of rss feed they would like.  These two functions would then look up this setting.  Thoughts?