Hard drive formatting for OSX and Windows 7 using GUID

Hey,

I am currently trying to format a 2TB WD Elements external hard drive so that I can use one half with Time Machine and the other half with Windows 7 (run using Boot Camp). From looking around online it appears that GPT is the best to use, and so using Disk Utility I formatted the hard hard drive into 2 partitions, one being Mac Os Extended (Journaled) and left the other as empty space. I then switched to Windows 7 (on the same machine) and formatted the empty space as NTFS. The problem is that now Windows 7 can see both partitions (and can see the contents of the HFS partition which I didn't think would be possible) but OSX can only see the NTFS partition (and has changed the label of the HFS partition from what I set to "disk0s2" when viewed in Disk Utility). I've probably done something very wrong, can anyone help?

Cam