thanks jim for your answer. i think that might be the solution for mike's problem (i'm pretty sure his is not the same question as mine), but my problem is the same as yours (launching the application, not the prompt for what to do with the files on the device / installer).
like you i use calibre exclusively and don't buy from the sony store, but i might start when they make the switch to epub, and i think i want to keep the access to google books (then again, i've so far not even registered with them, so maybe that's a sign that there's really no point.
). but i'm also running out of patience quickly so perhaps at the least i'll de-update and go back to the older version, now that i've installed the firmware update.
anyway, a solution for this would be great, if anyone finds one.
one note about your solution though, for me at least, the sony drive letters aren't necessarily always the same, since it depends on whether i've already got other usb drives plugged in when i connect it. but i imagine it shouldn't be too hard to correct for that.