Don't do it.
No matter how a sentence ends, it never ends in two periods. Want to tell us how much you love America? "I love the U.S.A." Want to say what time you're coming over? "I'll be there at 8:00 p.m." Or maybe you were wondering when World War I started. "It started in 1939 C.E."
Two periods looks funny, anyway..
See?