I don't know if this will help you but here are some instructions we used to provide on how to add third party plugins into the IDL workbench:
Supported dropins formats under the IDL directory structure

The dropins folder location in IDL is OS system dependent and will appear where the IDLDE executable is found. In other words, under Windows you will find the dropins folder under:
Install_Dir\idlxx\bin\bin.x86\

and for Windows 64bit, the folder will be under:
Install_Dir\idlxx\bin\bin.x86_64\

While under Linux and Mac OS the dropins folder will be located here:
Install_Dir/idlxx/idlde/

where "Install_Dir" is the main installation directory and xx is the software version.

The dropins folder can have four different layouts, that will depend on the complexity of the application that will be added to the IDL Workbench.

1- The simplest layout of directories is to just drop the jar file or the directory format plug-ins directly into the dropins folder:

Install_Dir/idlxx/bin/bin.[platform]/dropins/org.eclipse.core.tools_1.4.0.200710121455.jar/org.eclipse.releng.tools_3.3.0.v20070412/
plugin.xml
tools.jar
... other files ...

2- Traditional Eclipse applications or extension layouts can be directly dropped into the dropins folder:

Install_Dir/idlxx/bin/bin.[platform]/dropins/eclipse/features/plugins/

3- If the application has different components you can also add additional folders just immediately below the dropins folder where the traditional Eclipse extensions are located. For example:

Install_Dir/idlxx/bin/bin_x86/dropins/emf/eclipse/features/plugins/gef/eclipse/features/plugins/
... etc ...

where in this example "emf" and "gef" are different components of a particular application.

4- Also, similar to the Eclipse links folder, you can add link files:

Install_Dir/idlxx/bin/bin.[platform]/dropins/emf.link

In all the above cases, the "Install_Dir" is the main installation directory and xx is the software version. For example, for:

Windows: c:\Program Files\Exelis\
Linux : usr/local/exelis/
Mac : /Applications/exelis/

David
HGS