Hi Tobi,

the cable will hopefully be no problem, because the original iPod HDD was a Toshiba 80GB and the new one is also a Toshiba, but this time with 120GB.

Back to your problem. You can get adapters here:

http://store.era-ele.com/computer-adapte...

(I hope its ok to post external links)

As you need it only once, a simple adapter is all you need.

I think, that the size of the drive is not important, as i found a website with an offer to upgrade your iPod 5th generation to 240GB with an Toshiba HDD. So i think its rather the brand of the HDD than the size.

Crisb