The Malibu rehab facility where Britney Spears was treated earlier this year is the latest to join the growing list of subpoenas served by the attorney representing Kevin Federline as the custody battle over the exes’ two young sons continues.A Promises staff member was served yesterday morning. Mark Vincent Kaplan, Kevin’s attorney, confirmed to OK! that ‘an administrative assistant at Promises was served a subpoena today.’Britney spent four weeks at Promises and was released on March 21.Her former assistant and family friend Alli Sims, her bodyguard/manny Daimon Shippen as well as former personal assiatnt Shannon Funk have also been served legal letters asking them to give depositions which will focus on the singer’s parenting skills.Kevin dropped off the boys, Sean Preston, 22 months, and Jayden, 11 months, at Britney’s house on Friday before heading to Las Vegas for some partying.He checked into the Venetian hotel and then kicked off his evening at Tao nightclub with about 20 friends.An eyewitness tells OK! Kevin was surrounded by several women at a VIP table and that the group was drinking Grey Goose vodka, Jack Daniels and Jagermeister.’Kevin was doing was he likes to do best ? having a good time,’ says the eyewitness. ‘He was certainly interested in the women at his table. They were dancing close together at the near their table and cheering.’Kevin also spent his Saturday night at Tao. Seen again with a large group the rapper wanna be partied it up. An eyewitness tells OK!, Around 2am Kevin went up to the Dj Booth to see DJ Vice when he got on the mic and began to MC the evening. hyping up the crowd and rapping along to songs Kevin and his crew held the party and kept it going until 5am.Meanwhile, Britney was spotted showing off a new soccer mom look. She was seen driving her black convertible Mercedes wearing aviator sunglasses but without a wig ? she was wearing her blonde hair short and natural six months after shaving it all off.’It was a new look for Britney,’ says an eyewitness. ‘It suited her. She looked more comfortable than she has in a long time.’Photo: Wireimage

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