I have found the solution by my self :D. The default Cost is 10. And it's possible to verify the Password with Bcrypt.
$bycrypt->verify($pass, $passhash);
You get a boolean with this method ;D
The second solution is:
$newUser = new User();
$newUser->user_id = '';
$newUser->email = '';
$password = ''
$bcrypt = new Bcrypt();
$bcrypt->setCost(10);
$newUser->password = $bcrypt->create($password);
$userT->saveUser($newUser);
mfg ternes3