Southernwayfare

I have a Santana Moda that I use for commuting, low mileage touring, and the occasional century. I was considering doing a few upgrades and just ran into a problem. I like bullhorn handlebars and thought that, rather than use a straight bar with bar ends on this bike, I'd install bullhorns. Unfortunately, it seems like this won't work. The brakes and thumb shifters won't fit the diameter of the new handlebars. I did a little research and found out that older mountain bikes use 22.2 mm bars. Is there anything I can do besides buy another 22.2 mm bar?