After upgrading to Doctrine 1.2.2 queries with named arguments doesn't work anymore.
Whenever querying like
$query = Doctrine_Query::create();
$customer = $query->from('Customers')
->where("id = :id"
, array('id'=>$user['customer_id']))
->fetchOne(array(), Doctrine::HYDRATE_ARRAY);

I get the error
SQLSTATE[HY000]: General error: 10007 Incorrect syntax near ':'. [10007] (severity 5)

If changing the query to
$query = Doctrine_Query::create();
$customer = $query->from('Customers')
->where("id = ?"
, array($user['customer_id']))
->fetchOne(array(), Doctrine::HYDRATE_ARRAY);
it works fine.
Testing with MySQL works fine, so it seems contained to MSSQL