Ending a long silence here.
I finally handed in my dissertation in the end of March. According to the Finnish system, it was then sent for so-called pre-examination for two external examiners. They will read my dissertation and comment it. After that I am to do corrections and additions according to the wishes of the examiners. Only after that I can apply for a permission to defend from the faculty. Since I have not got the comments yet, and I have loads of work for this autumn, my defense may not take place until early 2012. Such a long, slow process, and I have not even got the external examiners' comments yet.