[galaxy-dev] Picard MarkDups

I'm trying to run Picard MarkDups through Galaxy. Picard is using the standard 4g for the java max heap size. I need to increase this. Is it possible to offer this as an option to the user? If not, where do I change this? I see the entry in picard_wrapper.py. Do I change it here or in the XML file for MarkDups? Ryan