Oil spraying device on Iraq He111s

[RolandF]

In an other forum I was asked by a friend concerning an article in "Jet and prop" about Luftwaffe´s Iraq adventure.
One caption of a totally wrecked and burnt-out He111 is as follows:
"The remains of an He111 of Sonderkommando Junck´s bomber component, 4./KG4, which was destroyed by British aircraft at Mossul on 22 May 1941. Note the tail pipe which was used to launch oil at fighters attacking from the rear, a device fitted to all He111s operating over Iraq."
I remember a photograph (William Green: Warplanes of the 3rd Reich?) of an Iraq He111H-6 5J+GM (overpainted) with some kind of tubular device visible at the tail.
Has this been an official conversion set, some kind of field conversion or is this totally bogus?
Some kind of small-calibre machine-guns - like on the Do217 or other planes would seem more reasonable to me...
Thx for any explanation and sorry, if there should be a thread upon this topic. I DID search...

http://i282.photobucket.com/albums/k...bon/iraq13.jpg
http://i282.photobucket.com/albums/k...bon/iraq22.jpg

Regards

Roland