Problem: battery replacement 2g iPod

But when I succeeded, ccording to instructions, back was supposed to lift off. But it won't
Bob Ball wrote on :

Got the Newer Tech battery and tools. Had a helluva time opening the case. But when I succeeded, ccording to instructions, back was supposed to lift off. But it won't; it wants to take the controls and headphone receptacle with it, as far as I can tell, and I'm not ready to force it off.

Any suggestions? It came from OWC, but I didn't quickly find a place on their site to raise the question.

The video on the site is aimed at 1G iPods although entry to the site suggests it's good for both. The hard to read (2point type?) indicates it's for 1g and 2g. Was there any difference in how the back comes off?