Hello Bernhard,
a found two interesting informations for you. See the following links:
http://forums.ni.com/ni/board/message?board.id=170&message.id=65413&requireLogin=False
http://digital.ni.com/public.nsf/allkb/A27678A81DAAA2C18625713A007B70D2?OpenDocument
http://digital.ni.com/public.nsf/allkb/2EFEF30C8E52168986257091006A9910?OpenDocument
It seems, that you can use
Tungsten PDAs...
I can't try it, but I hope these information will help you
Best regards
Dippi