mac - How can I make Boot Camp use unallocated space?

I have created a partition for OS X (200GB journaled, encrypted) and also left 51GB unallocated for Boot Camp later on.

After I successfully installed OS X 10.9, I wanted to install Windows 8.1 with Boot Camp.
But Boot Camp only wants to shrink the Macintosh HD partition, and doesn't want to use the free space left on the drive. So I switched to Disk Utility, to try it that way.
But in Disk Utility I wasn't able to create a new partition (if I press the 'partition' button it just doesn't do anything).

Next, I tried to switch of File Vault 2, let it decrypt itself, restart, and then try it again in internet recovery mode.
But still, I cannot expand the Macintosh HD-partition or create a new partition.

Disk Utility log:

2014-09-04 00:42:31 +0200: Preparing partitioning: 'APPLE SSD SM256E Media'

Also, Disk Utility tells me there is 200.000.000.000 bytes of 200.000.000.000 bytes used, and 0 bytes of free space. Even though not even half of the drive is colored blue (which displays the amount of data on the drive). Finder tells me only 88GB is used.

I used the new installation for no longer than half a day, so there can't be issues that data is spread over the whole volume.
Disk Utility can't find any problems, and tells me the disk and all of her volumes are okay (in green texts).

I also tried to start from a windows-install-usb, and tried to make a partition of the 'unallocated space', but then Windows tells me that it fails because the volume is part of the 'GPT partition style'.

What do I have to do to repartition my volumes!?

I'm using a MacBook Pro Retina 15" (MacBook Pro 10,1) with a 256GB SSD (251GB according to OS X).

Answer

Here is what I've done:

I started with this situation, I formatted 200GB of my drive for OS X and left 51GB 'unallocated' for a Bootcamp partition later. I turned on File Vault and installed my programs. I could not create a new partition out of the unallocated space with Disk Utility or the Bootcamp Utility.

Since Bootcamp could not create a partition from the unallocated space, I chose to split the Macintosh HD partition into 2 partitions with Bootcamp.

After that, I deleted the bootcamp-volume with Disk Utility. After deleting the Bootcamp-volume, disk utility expands the main-os partition to its maximum size by using all unallocated space. That solved the problem!