Thanks everyone for replying! I have tested it and it really works the way some of you have suggested: one must go to Windows Explorer (or My Computer, etc. just any incarnation of Explorer), RMB click on the Kindle as displayed among other drives and then select Eject from the pop-up menu. Kindle display goes to your home page or the latest book and the device probably keeps charging - at least if I am supposed to believe the orange/green LEDs at the bottom. Tested on Windows 7. Incidentally quite confusing here, because the RMB menu in the tray (next to the clock usually bottom right) really offers Ejecting Kindle. The similar menu under Windows XP offered to "Safely remove hardware" as far as I remember. If anyone knows the difference between the two options, it would be nice to know - just out of curiosity.
Best regards to everyone!
PH