I needed to convert from excel 2007 file to an CSV file with us-ascii encoding. after some long searches i found how it can be done using the libreoffice.

1. open the xls file with libreoffice.
2. save as Text CSV in the save as type:
3. click "use Text CSV Format"
4.  On Export Text file - Field options that pops out select Western Europe (ASCII/US), Filed delimiter ';' and Text delimiter ' " '.
5. click ok and you can test it on linux machine for file type encoding by typing file -bi <Filename.csv>
example:

#file -bi libreoffice.csv
text/plain charset=us-ascii
#

This is all you need do to. "it can be usefull for a lot more as the list was long, but i neeed only us-ascii"

Timi