Make 2 partitions.
Partition 1 as FAT. 100MB. Therefore Seeable and useable by all Windows since the beginnin of Win32.
Partition Number 5 and EXT2/3 filesystem.
Put the Windows Drivers for EXT2/3 on the 100MB partiton. That is why I said to use the first 100MB.
You could try it. Before you do anything with it. The worst is you'll have to re-format it again.
Remerber, First 100MB == Windows Drivers for EXT2/3, last 299.9GB == EXT2/3