Hi Roger
Since I am uncertain what it is exactly you mean, my comments may be way off the hill...
To me what is underneath the right wing which looks like a tubestructure is part of the strut and is connected both to the top wing and the strut itself. What looks like a rod pointing downwards is as far as can see on every Storch. A close up shows that it is graded and my guess is that it measured the fuel status in the wing. As far as I can judge it is also underneath the left wing.
The Fi 156 carried many different types and sizes of tanks underneath its belly and from the photos I have of the type actually carrying tanks (not that usual it seems), they vary a lot, but none looks like the one on your photo. Looks like Ed is right when he says it looks like its "glazed". No suggestions though...
Cheers
Stig
PS: Nice shot!