With a powered USB hub, will I be able to use an external hdd together+wireless dongle for kb and mouse together with my N900, or it is better to use Y-cable for HDD+charging and bluetooth mouse+keyboard for input? Will I have to power the hub right before hitting vbus boost button, or anytime before?

And a little off-topic, but it's very related. If I get a call, and have a bluetooth headset paired and audio connected to external source (TV. for example), once I answer the call, will I hear the caller only on headset, or on TV as well? If the latter, can it be fixed so that sounds from call go to headset only? (I wouldn't ask this stupid question if I had a bluetooth headset to try)