# Regex to find unicode characters that are not valid in XML
# http://en.wikipedia.org/wiki/Valid_characters_in_XML
invalid_xml_chars = re.compile(u'[\x00-\x08\x0B-\x0C\x0E-\x1F\x7F]')

# Create the temp file to hold the XML
xml = StringIO()

s = unicode(xml_tpl.format(data_obj))
xml.write(re.sub(invalid_xml_chars, u"", s).encode('utf-8', 'xmlcharrefreplace'))
xml.seek(0)

ftp = FTP(credential..)
# Set connection mode to active
ftp.set_pasv(False)
ftp.storbinary("STOR file.xml", xml)