Storing files outside of the Redmine directory

Hi. I’d like to be able to configure my Bitnami Redmine stack so that it stores its relevant data (wiki pages, uploaded files, etc.) into a directory other than that in which the stack resides. I realize part of the benefit of the stacks is that they are self-contained, but I’m looking for a semi-self-contained solution here. Any ideas?

Thanks,
Brandon W.