Correctly encode default_dateformat when converting from phpBB2

Hi,

I've experienced an issue converting the "default_dateformat" value.
My value is set for French language, using a "à". The value is this one: "d M Y à H:i"
And I got this error message when I launched the conversion...

SQL ERROR [ mysql4 ]

Incorrect string value: '\xE0 H:i' for column 'config_value' at row 1 [1366]

SQL

UPDATE phpbb_config SET config_value = 'd M Y � H:i' WHERE config_name = 'default_dateformat'

BACKTRACE

FILE: includes/db/mysql.php
LINE: 158
CALL: dbal_mysql->sql_error()

FILE: includes/functions.php
LINE: 148
CALL: dbal_mysql->sql_query()

FILE: includes/functions_convert.php
LINE: 1288
CALL: set_config()

FILE: install/install_convert.php
LINE: 987
CALL: restore_config()

FILE: install/install_convert.php
LINE: 203
CALL: install_convert->convert_data()

FILE: install/index.php
LINE: 402
CALL: install_convert->main()

FILE: install/index.php
LINE: 274
CALL: module->load()

Obviously, I have temporarily change the phpBB 2 default value to skip this bug but it'll be nice to fix it
Thanks!