Persuading Management on Green-Lighting In-House Software?

Raisin Bread asks: "Maybe I'm fighting a losing battle - but has anyone out there encountered an administrative resistance when it comes to giving approval to make in-house solutions for problems? I'm at a university, and we want to build a tracking system that will accommodate our needs perfectly (and can do it), but the boss wants the easy way out by contracting out to a remotely-hosted and managed solution. Sure, they are commercially supported, but the fix is only mediocre. What arguments have been used to sway the boss to use the super-cool home grown solution?"