PowerEdge R330 server could not downgrade OS

Hello,

I just purchased PowerEdge R330 for my office. it comes with pre-install Windows Server 2012 R2. However, I need to downgrade the OS as it's the requirement for some the software that need to be installed. 

Problem now, i could not downgrade the OS, even though i had inject my Windows 2008 installer with USB 3.0 driver (as per instructed in the manual).

I use 2 ways to re-install the OS.

1) Via windows: Error occurred - "Could not install required driver"

2) Via Dell Lifecycle Controller (OS Deployment) - system could not detect any hard drive/storage

Need some help to solve this.

Thanks!