Red Bull want to try and regain 6th place in the Championship and swapping drivers won't help their chances.
As for Vitantonio Liuzzi, it appears that he will get a drive in Formula 1 next year either with Red Bull Racing or the rookie team which Red Bull will setup after aquiring the Minardi team.
Red Bull Sporting Director Christian Horner said :
Full Red Bull StatementFollowing Red Bull GmbH?s acquisition of Minardi last weekend, Christian and Tonio have assured futures in F1. As a result, Red Bull Racing has decided to continue with Christian as race driver for the final three races of the year. Having contested the races previously, Christian will be looking to secure Championship points for the team, while Tonio?s role as third driver will allow him to familiarise himself with the circuits in Brazil, Japan and China ahead of 2006. No decision as to which driver will compete for the team alongside David Coulthard next year has yet been made; Red Bull Racing will announce its 2006 driver line-up after the end of the season.