Intent: To setup tables in the SQL Server database.
Mantis installation of tables under Sql Server seems to fail.
Looking at the install.php code, the problem seems to be in the switch-case statement for selecting the appropriate database.

Session returns ado_mssql or odbc_mssql whereas the case does not have this entry (it has only mssql).

Modifying the switch-case as follows seemed to solve the tables-installation problem.

switch ($f_db_type) {
case 'mysql':
$t_support = function_exists('mysql_connect');
break;
case 'pgsql':
$t_support = function_exists('pg_connect');
break;
case 'mssql':
case 'ado_mssql':
case 'odbc_mssql' :
$f_db_type = 'mssql';
$t_support = function_exists('mssql_connect');
break;
default:
$t_support = false;
}

This installs the tables but the insert of initialization data fails.
kThe workaround I used was to tweal the sql statements and exeecute them in query analyzer. The statements I used are below:

SQL 1:

-- here I set the fields to be inserted in, removed first field as its an IDENTITY field, also set cookie string to ''

INSERT INTO mantis_user_table(username, realname, email, password, date_created, last_visit, enabled, protected, access_level, login_count, lost_password_request_count, failed_login_count, cookie_string) VALUES ( 'administrator', '', 'user@domain.com', '63a9f0ea7bb98050796b649e85481845', '2003-02-16 02:03:48', '2004-07-08 23:59:22', 1, 1, 90, 3, 0, 0, '');

GO

SQL 2:

-- here I replace 51 with '51' as value is a text field not an integer.

INSERT INTO mantis_config_table ( value, type, access_reqd, config_id, project_id, user_id ) VALUES ('51', 1, 90, 'database_version', 20, 0 );