iPod 3rd Gen can I change the software to V2.2

Hi I have an iPod 3rd Generation (the one with the four buttons above the wheel) and I am trying to use it with a Harmon Kardon Drive + (the first version)

The Harmon Kardon says it will only accept iPod 3Gen running software v2.2 (2/04) and my iPod is running v2.3

When I connect the iPod the Drive + says iPod is disconnected.

Can I de-update to v2.2?

Can you tell me how?

Thank-you