How do you convert a Mac formatted iPod to be a PC formatted iPod

I have a 4G clickwheel iPod that has been used and formatted with a mac. Now I need to be able to use it with a PC which has iTunes 7 installed.

Everytime I connect to the PC, I get the following "iTunes Helper" window saying:

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An iPod has been detected, but the iPod software is not installed.

Please install the iPod software from the CD that came with your iPod or download the iPod Software Updater from www.apple.com/ipod/download.
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The iPod has Ver 3.1.1 and has been reset and restored via my mac.
But the error message above is just a dead end with an OK button. At no point am I given the option to install the software since the updater is now intergrated into iTunes 7 and iTunes will not display the connected iPod.

Any ideas on how to get around this?

Thank you.