When there're already 4 primary partitions on the disk, New Partition option will grey out in disk management, try the following steps to create one more partition.
1. New Partition Option Greyed out in Sever 2003 Disk management
2. Delete F partition (Before you do it, make a backup is recommended)
3. Right-click on unallocated space and click New Partition
4. Click 'Extended partition' in New Partition Wizard
5. Right-click on the free space and click New Logical Drive
6. Click Logical drive and click Next
7. Assign the following drive letter to F again
8. Format the partition with the following setting
9. Right click on the rest of free space and you can click New Logical Drive
