dual boot - How do I install Ubuntu alongside UEFI enabled Windows 8?

I recently (about a month ago) bought a Dell XPS 8500 Desktop with UEFI enabled Windows 8 Pro pre-installed. I am trying to install Ubuntu 13.04 64-bit dualboot with Windows on this computer. I don't know much about UEFI, but I think I followed the correct instructions to do this installation. Here's what I've done so far:

1. I have a 256GB SSD drive with the Windows OS partition and a 1TB drive for data. I created a 100GB partition on the 1TB drive for ubuntu. This was done through Windows Disk Management.




2. I downloaded Ubuntu and created a bootable USB as per the instructions on the Ubuntu website.




3. I tried installing Ubuntu through the USB.

PROBLEM: While installation, I do not see a "Install alongside Windows 8" option like I have usually seen in all my previous installs.

Now, I don't know if this has to do with UEFI and I don't know much about that anyway.

QUESTION: How should I proceed with the installation?

I am currently on the same computer through Windows. I also have access to a laptop with Windows 8 Pro (possibly not enabled with UEFI - it's an old computer with newly installed OS) alongwith Ubuntu 12.10 dualboot.

EDIT: I "tried" Ubuntu without installing it via the LiveUSB. It is not able to access any of the drives. Do you think that has anything to do with this issue? Any help would really be appreciated. Thank you so much.

You should defragment your Windows partition, as far as I know Windows comes with a tool for that.

Once defragmentation is complete you have to perform a "full shutdown" in Windows, as by default it does like a hibernation when shutting down. To do that search for cmd in Windows Search and it will point you to the command line prompt, start it and execute the following command:

shutdown /s /t 0 

Now you have to start a Ubuntu live session by booting a Live-USB and choosing the option: Explore Ubuntu without installing.

When the desktop loads up, start GParted and you should see the EFI partition at the start of the partition table followed by your drive C:\ partition, click on the C:\ partition and re-size it to make room for Ubuntu partition. Click on the "Apply" button of GParted and wait until it completes the operations.

Now start the Ubuntu Installator, when it prompts you for the installation type you should choose Something Else, the last option.

And now you just select the free space and click the + button at the bottom.

Create the new partition as Primary type, using Ext 4 journaling file system and setting mounting point to /.

After installation is complete just reboot and check if everything works fine. Although, as your Windows is installed in UEFI mode you can experience problems, such as booting straight to Windows and not passing through GRUB. For problems like that you should use Ubuntu Boot-Repair tool. Also check these Q&As if in trouble: Windows 8 doesn't allow Ubuntu start-up
and https://askubuntu.com/a/292783/21195 .