I've tried data process shape with decode and unzip but it fails probably because boomi can't unzip a file that doesn't have .zip extension, but I couldn't find a way to make decoded file a zip. I always end up with .dat file that i have to make .zip manually and that's really not what I want. I've tried custom scripting:
dataContext.storeStream(new ZipInputStream(dataContext.getStream(it)), dataContext.getProperties(it))
but it just returns .dat file too.
I hope that there is some way.