Windows XP RAID Capacity Limit

I understand the 2tb MBR limit, I understand this is because of the 32bit addressing issue with 512 byte sectors. I have also read in a number of places that one can increase the sector size to increase the usable capacity of the array.
So, I have 4 tb drives configured in a RAID 5 array, which should have a capacity of 3tb. When setting it up I configured it with 4k sectors. According to "teh intarwebz" this should allow me to address up to 16tb. This box is running Windows XP and when I go into the Disk Management console it shows the drive size as 2tb. I ran a checkdisk and was able to confirm that the sector size 4096 bits. I also went into my RAID card's management console and confirmed that the array was reporting 3tb as the size.
I'm wondering if there's anything I need to do or if it's just not possible to have a 3tb array work with XP even if I use larger sectors?

i dont know about xp32, but win xp64 i am definitely sure that you can have partitions bigger than 2tb. because the pc i'm using right now has xp64 and one partition with five 750gb drives in raid0... your other alternative, if it's a server box, is to simply go with linux on the box.