He's mentioned in the book "The Naval Policy of Austro-Hungary" as a Rear Admiral in command of the Danube Flotilla in 1917. Austro-Hungary was split apart at the end of WWI, and part of the Danube Flotilla ships were confiscated by the newly formed Kingdom of Yugoslavia. It is likely that Wickerhauser kept his rank and position in the new Royal Yugoslav Navy.
Here's a list of Royal Yugoslav ships:
http://en.wikipedia.org/wiki/List_of_sh ... oslav_Navy
I speculate that Rear Admiral Wickerhauser was in command of the River Fleet which included four Ex-Austro-Hungarian monitors that were renamed Vardar, Sava, Drava, and Morava, which originally served in the Danube Flotilla.