Custom DatabaseConnection driver does not get found by drupal! I need to customize a method on the DatabaseConnection_sqlsrv (MSSQL) driver, so i created a new driver class called DatabaseConnection_sqlsrvseed and extended all depended classes  from the *_sqlsrv classes.

class DatabaseConnection_sqlsrvseed extends DatabaseConnection_sqlsrv {
  public function driver() {
    return 'sqlsrvseed';
  }
  public function databaseType() {
    return 'sqlsrvseed';
  }
}


Basically all other classes in the database/sqlsrvseed folder are empty classes that inherit their functionality from their parents like this one: 

class InsertQuery_sqlsrvseed extends InsertQuery_sqlsrv {}


I am doing this because i need a modification on createFieldSql in DatabaseSchema_sqlsrv to create IDENTITY fields with a Seed value. 

However, whenever i set 

$database['default']['default']['driver'] = 'sqlsrvseed'

i get the error: 


  Fatal error: Class 'DatabaseConnection_sqlsrvseed' not found in
  C:[...]\includes\database\database.inc on line 1686


Although i am pretty sure that the class and all dependencies exist.
I did excactly everything like they did it in the sqlsrv driver: 


  Drupal and the SQL Server driver Uncompress Drupal in the web root.
  Uncompress this driver as sites/all/modules/sqlsrv, and copy or link
  the sqlsrv directory found inside it in includes/databases.


So I copied the files from database folder as well as the module folder. But there is a strange difference. I can't activate my custom driver module, whereas i can activate sqlsrv one. Any help? How does drupal gets to know this driver, without core modification?
It looks like Drupal's autoload failed. For it to work you should put your classes in .inc file in your module, and then mention it in files line of module's .info file.

If that does not help and your classes are needed even earlier, include them in your settings.php:

require_once('path/to/module/sqlsrvseed.inc');