Ernesto
I found this in the configuration manual for the IPS:
The following password recovery options exist:
?If another Administrator account exists, the other Administrator can change the password.
?If a Service account exists, you can log in to the service account and switch to user root using the command su - root. Use the password command to change the CLI Administrator account's password. For example, if the Administrator username is "adminu," the command is password adminu. You are prompted to enter the new password twice. For more information, see Creating the Service Account.
You can reimage the sensor using either the recovery partition or a system image file.
If you want to see more detail here is the URL:
http://www.cisco.com/en/US/products/hw/vpndevc/ps4077/products_configuration_guide_chapter09186a008055dfcd.html
HTH
Rick
HTH
Rick