There is a topic on Alphasmart in the Scrivener Forum.
By the way, Umlaute created with the compose feature on an Alphasmart with an English keyboard, show up as gibberish when "sent" to an application on the PC (and the Mac, I would suppose). They show up correctly when the files are transferred with the Neo Manager (which also works with Windows 7 (64 bit).
Scrivener for Windows is supposed to be released on the 25th of October.
1. I use ";a", ";A", etc. in AutoHotkey to produce "ä", "Ä", etc. on the PC. If I use ";a", ";A", etc. in an Alphasmart file and then send it to an application, the Umlaute also get translated properly by AutoHotkey. I prefer this solution, as it is quicker and more convenient.