Long term email archiving\Journaling in Office365

About 6-9 months ago I was looking to migrate a bank to O365 and they have to meet compliance rules about email retention.  Not only retaining email but retaining a read only copy of all email, a.k.a journaling.   Currently we have email journaled to an appliance in house and our Exchange is in house.  The last time I talked to the MS sales guy I was told that there was a method of archiving/journaling in O365.  I am migrating us to O365 soon and can't find any method of journaling.  The Sales guy used the phrase Data Loss Prevention but that doesnt look like journaling, especially since they have a journaling option in O365 already.  My searches have told me that MS does not offer a method to journal online, only external (see below).  Can anyone verify that?  

“Journaling mailbox   The journaling mailbox is used for collecting journal reports. How the journaling mailbox is configured depends on your organization's policies, regulatory requirements, and legal requirements. You can specify one journaling mailbox to collect messages for all the journal rules configured in the organization, or you can use different journaling mailboxes for different journal rules or sets of journal rules. The journaling mailbox specified in a journal rule must be external to your organization.”