The reason why you don't get the expected results is because of the existence of "unmovable" files which are spread over your volume (for example and the end).
These system files could be your paging file, hibernation data, shadow copy data and even your Master File Table (MFT).
Now you could do a couple of things:
Disable as many of the system files as you can and do a defrag of your volume and try again. Now not all defragment tools are capable of moving the MFT file but maybe your lucky and you don't to. Don't forget to enable all of your system files again. Also read this article as it gives a good description of the tools you can use, and the steps on how to disable your system files, even though it's for Windows Vista it shouldn't be to hard to apply them for Windows 7.
Use third party tool for this. The reason why Disk Management isn't working like you expect is that because Disk Management is run within Windows and is prohibted to move these files. Most of the third party software work outside Windows for this reason. Example of third party tools are: Acronis Disk Director, Paragon Partion Manager.