HBO picked up “American Beauty” scribe Alan Ball’s new series “Six Feet Under,” and will likely preem the skein in March following episodes of “The Sopranos’ ” third season.The network is negotiating the number of episodes in the order, but the buy will likely be for 12 installments. Ball, Robert Greenblatt and David Janollari are exec producers of the skein, a production of the Greenblatt Janollari Studio. Alan Poul is co-exec producer. Skein focuses on a family that owns and operates an L.A.-based funeral home. The pilot starred thesps Frances Conroy, Peter Krause, Michael Hall, Lauren Ambrose, Rachel Griffiths, Freddy Rodriguez and Matthew St. Patrick. HBO’s next new series to debut will be Larry David’s “Curb Your Enthusiasm,” which preems Oct. 15 at 9:30 p.m.