John, Serge, thanks for your help! utf-16le encoding didn't help. I had however to solve it yesterday, so I used csv module to create CSV file and then import it in Excel. Excel still had troubles with accented characters, but this is another story: it seems that Office 2004 Excel (for Mac, but I assume the PC version is no better) cannot import UTF-8 encoded text files. Encoding CSV file with Latin1 encoding finally did work.
Now back to the Excel story, I also think that there is something wrong with pyExcelWriter or the way I use it. CSV file generation was okay, so I think there is nothing wrong with my data, or XML parser. I will resume in a few days with pyExcelWriter and will post the results here, but anyway, many thanks for your time and explanation! -- Ksenia -- http://mail.python.org/mailman/listinfo/python-list