He has yet to accept a one-year extension at Fratton Park, which was automatically offered due to his appearances last season.
Redknapp told The News: "Peter (Storrie) is sorting it out. As far as I know he's going to sign for another year and I want to keep him here."
The Nigerian, capped 39 times by his country, rejected claims he wanted a two-year deal, insisting there were "no problems" with the club's offer.
The former Arsenal striker has been a hit for Pompey since his move from West Brom two years ago, scoring 14 times in 15 league starts.
The 6ft 5in striker scored Pompey's winning goal in their 1-0 FA Cup final triumph over Cardiff.
Redknapp said Kanu still had an important part to play in Portsmouth's season despite the club signing strikers Peter Crouch from Liverpool and Ben Sahar on loan from Chelsea.