Problem connecting to MS SQL Server

[eluser]Circus-Killer[/eluser]
I am having troubles connecting to a MS SQL server.
Here are the values set in database.php:

$active_group = "default";
$active_record = TRUE;

$db['default']['hostname'] = "***.***.***.***";
$db['default']['username'] = "****";
$db['default']['password'] = "****";
$db['default']['database'] = "lso_new";
$db['default']['dbdriver'] = "mssql";
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";
$db['default']['dbcollat'] = "utf8_general_ci";

I have no idea what the problem is. I think it may have to do with the charset and dbcollat values. i'm pretty sure that dbcollat value must be "SQL_Latin1_General_CP1_CI_AS". but i have no idea how to figure out what the char_set should be.

if i am wrong about the dbcollat or someone knows what the charset should be or how i can find out what the charset should be, please let me know.

thanks in advance.