I would suggest hitting your local art supply 
store and picking up a roll of this wonderous 
substance.  All the same nice acid-free properties 
as archival paper, in that it'll never discolor or 
degrade the surface to which it's applied.  This 
is the stuff tht the pros use to secure artwork to 
matting during the framing process, and I'll bet a 
strip of it across the back of that rip would 
secure everything marvelously.

Good luck!  :)