Looked at the pictures again, re-read the original post.

Sorry, I missed the bit about the elbow being in line with the hole on the inside of the coolant cap.
I thought it was into the coolant reservoir. But it seems that it just goes through the casting and into the cap assembly between the two seals.

So, on second thought, it is a normal setup.

Just clear the hole. Poke, pick, drill, whatever. If you fill the header/exhaust tank up to the top of the cap assembly, the coolant should run out the hole into the pipe.