You can't if it is government related.
BTW as a 27 year veteran of the sys admin camp, since when have programmers been "above" sys admins? Respect disappeared when we stopped being system managers and became sys admins. Instead of managing things we administered them sounding more like an admin assist. That's I'm glad my title is engineer or consultant depending on the day.
IMHO, your best chance at compensation is to be creative. Comp time? Time to monitor campus classes (or take them for credit.) Agreement to change your title without a raise. Title's look good on resumes. Job flexibility in general tends to come to employees who go above and beyond.
How about a signed agreement that the software and copyright are yours and that you'll continue support and development outside of work hours for free allows you to own the software and a chance to make it marketable.
If you're looking for cold hard cash I think you are out of luck. Let's say the college finds the budget. Why would they necessarily select your solution? Oh and BTW you can't be on the selection committee as you have an inherent conflict of interests. In fact even selection of your solution would create substaintial conflicts.
If you're a government run/owned college the rules will be even tougher on conflicts of interest. Be VERY careful in that case trying to extract cash from this situation. Otherwise a felony conviction and prison time are not outside the realm of possibilities.
(Disclaimer: I'm an HP Employee)
But let me use an example wholely within the HP environment. I can buy new, refurb consumer or used refurb'ed business PC. I never go the business PC route for personal use as because I get less horsepower for the buck. Theoretically what I'm paying for in a business machine is higher reliability and lower support costs. However when the support cost is personal time that costs $0 to me, I pay the lower cost.
So I posit is that if cost of support labor and downtime is low, then the self build self support model makes sense. If the cost of labor is higher, then paying for a higher qualtiy, more reliable, extrenally supported solution makes more sense. Those labor costs need to include cost of down time of idled employees as well as support costs.
I disagree that noone born after 1990 wants to play pen and paper D&D. My two boys ages 9 and 13 are hooked. My 4 year-old daughter wants to play SO BAD. There is a whole gaggle of boys at scouts that have been roped in. Of course maybe that's because ipods, cell phones and computers are banned at overnighters! But that's not really the reason.
Why did I show D&D to my boys? The answer will surprise you. My older son was then 8. He was an advanced reader, but he much preferred books on tape, CD or later iPod. However none of the D&D books, my AD&D versions in particular, had audio versions. He had to wade through them himself. Seriously, how many 8 year olds are reading and trying to undrestand what a theocracy is. Then he wanted to take over and refurbish the moat house in one of the modules. He then needed to figure out the costs in GPs to plan. Enter the need for Excel!
D&D has been a tool to teach Microsoft Office skills, governments, reading, folklore, map making, budgets, medival culture, etc. I highly recommend it as a cirriculum for home schooling! Okay maybe that's taking it a bit too far.