You're the man, Charleski! Thanks.
I still get some funny results. Stanza has not changed its behaviour. It gives me no italics but shows the pinyin correctly. Adobe works fine with both italics and pinyin. Calibre turns everything into italics, and shows the pinyin correctly, and my Iriver shows both italics and pinyin as it should.
I must have missed the closing bracket once when I copied the @fontface statements, and not noticed it even when Valloric pointed out the small 'f' instead of a capital 'F' in the Fonts path.
I'll have a look at what you mean by the numbers at the end of the names of the font files. Don't know where they came from.
And I noticed the non-breaking spaces and assumed this was added by either calibre or sigil and wondered why ems weren't used, but was more concerned with getting the pinyin and italics showing, so I didn't do anything about that. Now I'll try and learn how to do that, and Zelda's epub of TMOAB should help me there.
Anyway, you've solved my problem for me, and I'm extremely grateful. Now I'll set about including the jpegs in the appropriate place, and I can load my own novel onto my own ebook reader, and maybe even upload it somewhere and see if it wakes any interest.