Central Kentucky veterinarian David H. Lambert has sued the Allen Paulson Living Trust for reneging on a deal that Lambert claims gave him a half-interest in two horses -- Horse of the Year candidate Azeri and 2001 Kentucky Derby starter Startac.The suit claims Allen Paulson promised Lambert the interests in Azeri and Startac for services provided, which were not specified in court documents. The Lexington Herald-Leader reports the suit also claims the agreement had been honored by Paulson until his death in July 2000. However, the Paulson Living Trust then reneged on the deal. The trust is currently overseen by co-trustees Michael Paulson, Allen Paulson's son, and Dr. Nicholas Diaco.Azeri, who was the unanimous selection for champion older filly or mare in 2002 and favorite for Horse of the Year, is scheduled to sell along with Startac as part of the remaining Paulson Living Trust dispersal at the Barretts Equine Limited 2-year-olds in training sale in March. The plan to complete the trust's dispersal in three phases beginning at Barretts was a result of an agreement reached in December between Diaco and Michael Paulson.