This is a rough draft - working on screenshots, and double checking the procedure. YMMV

Initial Configuration For Debug

Eclipse versions:
Eclipse IDE for C/C++ Developers http://www.eclipse.org/downloads/moreinfo/c.php (Galileo)
Eclipse Java Development Tools
Start Eclipse
Choose a workspace path of the form: workspace/OCAPRI/trunk/ri (Eclipse will create the directories).
In a bash window:

cd workspace
svn co -N https://community.cablelabs.com/svn/OCAPRI

In Eclipse:
New C++ Project: Project name: RI_Platform
New Java Project: Project name: RI_Stack

In a bash window:

cd workspace/OCAPRI
./checkout_dev_env.sh -force trunk

In Eclipse:
Refresh both projects

In bash window:

cd workspace/OCAPRI/trunk/ri
ant

When ant finishes, the RI will have been built (outside of Eclipse).

Adding a Debug Configuration

NOTE: For reasons not understood, certain configuration variables must be set for the Eclipse process (not configured in the debug configuration).
To simplify this (and make it easier to work with various branches, etc.) there is a bash script (OCAPRI/trunk/ri/start_eclipse.sh) that sets up the environment
and starts eclipse. For it to work eclipse either has to be on your PATH, or ECLIPSE_HOME has to be set appropriately.
In Eclipse:
Run->Debug Configurations
Right click on C/C++ application, choose New.

It is somewhat easier to show screenshots of the configuration tabs:

You should be able to launch a debug session.