Interesting; I'd missed this when I first read the thread.. I've found CSV to be unreliable as a copy/paste source, and generally use TSV which is astoundingly reliable in Excel.

Doesn't solve your problem, of course; you still need to know which semicolons to convert to tabs or commas and so this hasn't helped you at all -- just a note from a fairly heavy Excel user, in case it helps you in the future.