Just use levers. My Vittoria Randonneurs were a pain to install on my Xero XR-3s. The first one took an hour and a half of fighting it with my bare fingers. For the second one I just poked around online for advice on using levers to install tires. Go slow, be patient, and it shouldn't be a problem.

Once you learn how to mount a tire with levers it makes any future stiff tire mounts way easier.

Oh, and use steel core levers. The "unbreakable" plastic ones don't take much, I've found.