I've rambled too long and I am sure other people out there can bring more depth to the discussion. Focus on ways conferencing benefits the campus as a whole. Conferencing brings recognition and exposure to a college or university campus. Admissions will agree that exposure is always a great tool in recruiting new students. Also, your largest client base is in your own backyard.
Chances are that every staff and faculty personnel is a member of some sort of association.
Why not bring their association's regional or national meeting to their own campus. This gives the individual a chance to showcase their own academic and department achievements. Once again, bringing recognition to that campus' academics and achievements. You need concrete numbers showing a dollar value conferencing is bringing to the campus. In the case of an auxiliary, your revenue is helping keep the facility operating.