STDERR & STDOUT when running java from RPGLE

I'm sure I'm overlooking something pretty basic but even with my ninja Google skills I have been unable to determine how to make what has got to be a simple switch.

I'm running java from RPGLE after redirecting stdout by setting the envvar QIBM_RPG_JAVA_PROPERTIES with the value -Dos400.stdout=file:/myfolder/myfile.txt;
and setting QIBM_USE_DESCRIPTOR_STDIO to Y.

My output is properly going to the file, but each time a new job starts, it replaces the existing file when I would like it to append.

Is there another environment variable or a different value that someone can share?

Thanks,
Troy