What worked for me last year was convincing management that usage of Open Source Software meant involvement in Open Source. I pointed out that the convention afforded a rare opportunity to show that involvement. This year unfortunately that didn't cut it, as the focus is moving the company into the J2EE space. With only one talk scheduled on JBoss (Using JBoss.org: A Java 2 Enterprise Edition-based Container) and the fact that all travel expenses are drastically cut back this year I was unable to find a pitch that worked -- Still hoping for next year though :)