if you on the the security override switch it should override the iLO security. so you can login iLO via browser with administrator right. and once you are in iLO you can change your iLO user password.
Then logout from iLO. set the security override switch off and access iLO with the new password.
this way you can recover iLO Administrator password and overcome iLO login problem.
if i am not wrong switch 1 of maintenance switch should be iLO override switch.