Steffan Phiaff, who replaced Florian Schneider in Kraftwerk is not doing the music on stage, he's dealing with the actual visual side of the band. Ralf Hutter probably wanted to keep Kraftwerk a 4 piece band, hence putting Steffan in Florian's stage position on stage. The console Steffan uses is a video mix system, as in their last on stage track 'Music Non Stop' you will note Steffan steps off stage well before the track has finished and it is Henning Schmitz, Fritz Hillpert and Ralf Hutter doing all the music on stage. Both Henning, Fritz and Steffan were origionally part of the Kling-Klang Studio production staff but were bought in to replace Wolfgang Flur, Karl Bartos and Florian Schneider-Esleben (As that is Florian's full name)
The Band continues on into 2010 with a promised new album maybe out soon, or next year, as Ralf Hutter has hinted. It might be interesting to note that the Kling-Klang Studio is no longer in dusseldorf itself, but Ralf Hutter has purchased a new building where all Kraftwerk's administration, Music Production and Rehearsal room for live shows is now based. The origional building which Kling-Klang studio was based is no longer used. With the advancement in technology, i guess the band don't need such a large space as they tend to use small podium mounted instruments, although i expect the band also has a huge bank of instruments all rack'ed up by the production area of their new studio.
Ralf, Henning, Fritz and Steffan are now Kraftwerk, and the band is still producing music, although there has been a great number of peronelle changes as well as stylistic changes since the band first became a unit in 1970! It is a band i respect very much and one i hope will continue on well into the future