unfortunately he called last friday 1 minute before his own working hours ended and i didn't expect a call this late. then we rescheduled for a call yesterday but he did not call me. today, here in germany is a holiday (day of german unity). so i hope he calls back tomorrow.
edit: now i had the conversation with the executive relations advisor. he called from ireland (at least his caller id was from ireland). long story short: neither the support guys nor he is allowed to tell me what speeds the devices support because even they don't know about this stuff. he told me a fitting analogy: it's the same thing with the amount of ram or specifics of the cpu. apple does not disclose this information.
sorry guys