I might be able to help. The asym setup of the H20 should look a lot like the J/70, which I know well. Here is the cabin of the H20, without the pole (but ready for one).
Now the J70. Same angle. You can see that the line use to extend the pole is attached to the aft end of the pole and runs forward to a block, and then back through the bulkhead. The pole with the USA sticker on it is the boom in storage. The line on port is the furler, ignore that.
Outside. You can see the line coming through the bulkhead. Yes that can leak. The line is pulled to extend the pole, then cleated. When you are done with the pole, the line is uncleated, and the tackline is pulled in to retract the pole. On the 70 the tackline runs along the deck to a block at the pole end, probably on the H20 as well.
EDIT - This picture dos not show the pole line coming thru the bulkhead, so it might terminate and cleat inside. Same effect, just much harder to use say while racing.