Bob Ambrosini has ankled his post as chief financial officer of BET.Ambrosini joined the net in 2000 and helped guide it during its acquisition by Viacom. He will leave to pursue other professional endeavors. “My time with BET has proven to be both rewarding and challenging,” Ambrosini said. “I’m very grateful for the confidence that Viacom and BET placed in me during my tenure. Now that the merger and subsequent integration with Viacom is complete, it is time for me to seek out other media-based challenges.” Ambrosini came aboard BET from Texfi Industries, where he had been exec VP and CFO. A search is under way for his successor, said net prexy and chief operating officer Debra Lee.