Stefanie Ball has been named director of sales to oversee all of AT&T’s retail stores in Hawaii, the company said Monday. Ball, who will be based in Mililani, has been with AT&T (NYSE: T) for 10 years, most recently as area retail sales manager. “She is committed to AT&T’s growth and development in Hawaii,” Tammi Terrell, vice president and general manager for AT&T in Hawaii, said in a statement. “Moreover, her breadth of experience will be a tremendous asset to our region and our customers.” AT&T…