Arenas Entertainment in Beverly Hills will be marketing and promoting ABC shows to the U.S. Hispanic audience. of particular note are "Desperate Housewives," now entering its third season, and "Ugly Betty," a new series this fall that is an adaptation of a Colombian novella called "Yo Soy Betty La Fea." Ironically, "Betty La Fea" ran a few years ago on the NBC-owned Telemundo network. It's the story of plain and unfashionably dressed Betty who manages to find success at a snooty fashion magazine. Already, there are suggestions that it's politically incorrect. The show will air in the enviable Thursday 8 p.m. slot, opposite the Univision hit "Ugly Lety" (one more and we've got a trend). By the way, Arenas was started up in 1988 by Santiago Pozo, a former marketing executive at Universal Pictures. Pozo said he arrived in Los Angeles in 1983 on a tourist visa, speaking no English, with very little money, and knowing only one person in the United States. He spent a year working at assorted tasks, including being a janitor, while he learned English and successfully applied to USC. In its work for ABC, Arenas will be responsible for creative work as well as strategy and media planning-and-buying, all targeting Hispanics.