title: login with credentials fail with sfDoctrineGuard in symfony 1.4
body: <p>So I've this application and have to grant access to type of people the admin and a little group of people who have to edit a little part of an module. 
  Lets say I've a module which has fields [A, B, C, D], and a group of people need to change the default value of some os the items that module represents, for instance C and D.
  Now I've created the the groups, setted the permissions and assigned the test user to that group, editted the security.yml like this: credentials: [[admin, certificatore]] as i need to be an or. Try to access it's not letting me in. where i'm going wrong? myUser extends the sfGuardSecurityUser. </p>
  
  <p>I've noticed that in DB the user, group and permission I've created are not present, but from the backend i can see them... </p>