There is a small tool available to download on forums page which will allow you to change the modified date on books so that you can order book manually according to your needs. This tool is mainly meant for Sony PRS-650 digital reader. I can easily choose the book from Home screen after ordering them. I heard that this app will work on x50 models and the 900.i have given the link Below:
OrderBooks for Mac v0.3.zip (46.4 KB)
OrderBooks for Windows v0.3.1.zip (15.7 KB)
OrderBooks for Windows v0.4 BETA.zip (265.3 KB)
Bookmarks