Anna Nicole Smith's ex-boyfriend LARRY BIRKHEAD insists the model's mother VIRGIE ARTHUR is "not his enemy", despite failing to settle a custody agreement. Birkhead, who was named the biological father of Smith's daughter Dannielynn last week (ends13Apr07), has refused to sign legal documents to agree to joint custody with Arthur. He says, "If she wants to be a grandmother, she can be a grandmother; my mum wants to be a grandmother too, but I'm not going to sign a paper saying so, it's just not right." Arthur has been pushing the photographer to sign over joint guardianship, claiming the tot also needs to be cared for by a member of her maternal family. Attorney Debra Rose, representing Arthur's case, says, "She truly cares. She deeply cares. Her faith in God leads her to believe that at the end of the day she will be in a position to assist with raising her granddaughter." Smith died earlier this year (Feb07) from an accidental drugs overdose, six months after the birth of Dannielynn in the Bahamas.