[galaxy-user] known name outputs shown in /database/files but not in galaxy windows

I have made a wrapper that has a tool that giving it an input file, gives you two output files with known extension: .gem and .log I call the tool with a python file, and I pass it the input file and the two output file names for galaxy to show them, but when I look into de database/files/000/ i get four files:

dataset_54.dat (my first declared output that it's empty) dataset_54.dat.gem (the output that throws the tool) dataset_54.dat.log (the other output file that throws the tool) dataset_55.dat (my second declared output that it's empty)

So,what I'm getting in the galaxy interface is _54.dat and _55.dat, both empty, instead of _54.dat.gem and _54.dat.log that are the good ones. How can I fix these? Thanks