Most of what you need to know is in here:
http://wiki.xbmc.org/index.php?title=MythicalLibrarian It looks kinda confusing, I know... I just had to fit alot of information in one page.
In order for mythicalLibrarian to run on your setup, you're going to need to process jobs on the recorder. Some setups have multiple backends processing multiple jobs from other backends. You must disable this in mythtv.
Unfortunately, symlinks do not work across SMB shares, so you want to stay away from link mode... Microsoft implemented SMBFS before NTFS 4.1. SMBFS works like FAT. So symlinks are not acceptable.
The most appropriate method for your situation is to use MOVE mode. Tell MythTV to follow symlinks when deleting so that everything stays in sync. The backends will still serve the file, following the symlinks appropriately. The backends will also modify and delete the files just like normal.
In MOVE mode, you will share the /recordings/Episodes, /recordings/Showings and /recordings/Movies folders. This way XBMC can differentiate between them... They get handled differently.
As far as I know, we can't communicate with Boxee to automatically update the library, so you'll have to manually scan, or set up something to scan automatically.
I'm not sure how things will work with mythlink. You should try to undo whatever mythlink did.. You can also run mythicalLibrarian /path_to/testfile.mpg before you do a mythicalLibrarian --scan.
Btw.. use the SVN version.. There was some problems with folder names with spaces in the current stable. I havn't made a new stable yet.... I'll get on that.