I also like the auto-save feature and have also switched it on for
buffers not visiting files. However, whenever I am writing a mail,
emacs tries to save it into an auto-save file with asterisks in its
name, which doesn't work since this is a forbidden character on VFAT.
I have tried customising auto-save-file-name-transforms, but this does
not work, apparently because make-auto-save-file-name only uses it if
the buffer is visiting a file (does anybody know why on earth?).
Is there any standard way to make make-auto-save-file-name use it also
for buffer names, or do I simply have to hack the function?