One of the underlying technologies used for this is SAML, and you can seem more information about how we do it in this blog post I wrote after setting this Vordel-OSB interop up myself. You can follow these instructions to setup the identity propagation scenario.
In the diagram below, the Vordel Gateway is working with a number of Oracle IM products (OAM, OES, OVD, OWSM - see a naming pattern there? ;=) ) to provide end-to-end identity propagation from the edge of the network through to the app server.
For more information about Vordel Gateway interop with many Oracle products, check out http://www.vordel.com/oracle