R230 stalling problem
 

My brother has asked me to post a problem he has with his brand new R230. It is a SL500 equipped with the new 7G-Tronic transmission (as an aside I ask you, why a seven speed transmission? why?).

Several times now upon rapidly pulling away from a standstill (but not full throttle or kickdown) the engine has stalled or cut out as the transmission shifts from first to second. The change takes place at about 5,000rpm.

Any ideas? It sounds to me like engine, fuel system and gearbox aren't talking to each other but what would I know.

The car is fully warranted but neither I nor my brother would trust the dealership to diagnose and solve the problem.