Which action in particular are you trying to do with this? BusinessRulesProcessor? XPathRouter?
DroolsRuleBaseHelper says in the comments that a file on the classpath or an URL will suffice, but I haven't tested that out, classpath and URL options don't seem to be tested in the unit test, and DroolsRuleBaseHelper.getRulesInputStream makes me suspicious about whether that would work.
My guess - if the classpath/URL options don't work - would be that you might have to change DroolsRuleBaseHelper.java to do what you want it to do, but the change seems pretty trivial and it would result in you having to swap out one JAR file.
If you find that the classpath / URL options don't work, please let us know here in either a JIRA or just a follow up (and I'll file a JIRA based on that).