iTunes should not require the Surface hack to access the data on the card. The current Metro Apps configuration requires you to 'hack' or redirect the OS to the SD card in order to access data on the SDCARD from Metro apps. .
The bottom line is you create a folder on C: called SD or whatever and then use disk manager to point it to your SD card after you create the Pictures, Music and Movies folders on the SD. Once that link is a library, Metro apps can see the card.
I do not believe that this should be required for ITunes if its a desktop application. I use media player instead of XBOX Music and bypass the need to hack the OS, though I have hacked mine for good measure. I just need to reformat the card to NTFS and I currently have all my music on it in FAT32 and have been too busy to bother.