I got my retrieval line threaded through my beam. Thanks for the suggestions. I ended up doing the following:
1) The end-caps on my forward beam have two holes in them, a small one that the bungie line goes through, and a larger one that looks like an inspection port.
2) I threaded the bungie in the small hole on the starboard side and then out the large hole on the starboard side.
3) I duck tapped the end of the bungie cord to the end of my tiller extension, which happens to be just thin enough to go through the larger hole.
4) I pushed the bungie through the large hole on the port side and untaped it, then removed my extension from the beam.
5) threaded the bungie through the small hole on the port side. This was the hardest part of the whole procedure. It required making a paper clip hook, inserting that into the small hole, hooking the bungie and pulling it through. This was difficult because the bolt that holds the beam onto the hull was in the way and my fingers were too thick. My daughter's fingers were small enough though! I knew having that kid was a good idea. :-)