Version 5.1.2 of C-EMS is available for download since yesterday (Oct 11th 2010).
This version comes with the following new feature:

Any HTML and HTTP connector now has a new table property named "HTTPHeaderForward".

With this property you can list all the HTTPHeaders that C-EMS should forward to the target Web applications.
For each HTTPHeader you can define whether it replaces the original HTTPHeader or it is appended to it.

One typical use case is to forward user credentials when using a 3rd-party Single Sign-On product.