Use the vita book edit from this thread.
Set the with " change folder location" to the drive where your micro sd is and then add books.
It copy the books in the correct folder with the covers and all files.
I don't knew if books without covers does work or not
my reader settings are not saving changes. is that normal i disable sync at startup but i still get the message and i uncheck guidebook visible but its not saving am i doing something wrong i can still see the guidebook