Howzit
try going to terminal and type the cmd file filename this will tell what type the file is then try choosing the right association. The only reason I can see that the file reverts back to the original is that the extention is changed but the file header is still the same. Linux see the header then reverts it back I´m not sure how to change this. vi /usr/share/magic this is the place that id the files on u´r system
Don´t know if this helps but hey at least we try
chow