Custom Adapter Module with Build Path External JAR

[isudoajl_ine]

Hello experts,

My scenario:

Development Infrastructure
  Software Component
    Development Component
      EAR (Referenced Projects: My EJB localdevelopment)
      EJB

The custom module logic (validating the XML before it is processed) was created separately and was added as an external JAR in the EJB localdevelopment Project.

My current module class dont have compilation Errors (Syntax Errors) but Build errors when Build gets executed.

The error import classes are those from my external JAR:

As far as I have been able to find out, setting the Build Path is not enough.

Im not sure but Im think there are 2 ways to resolve this: 

- Create an External Library project:

Source: Using External Libraries for Development with NWDI 

The above approach Using Exteral Libraries I think need to be linked with the Deployment descriptors.

Deployment descriptors 

- I found another resource Referencing an External JAR File

Source: Referencing an External JAR

Questions:

Is this the only way to handle external libraries in an EJB or is there another way that is easier?

The following post make references in the application-j2ee-engine.xsd but I don't see that the person have created an External Library DC:

How to create SAP PI adapter modules in EJB 3.0 

What exactly should I do? So far, beyond referencing the EJB in the EAR at the time I create it, do I need to do anything else?

I have done the research, but I see different procedures, can someone help me decide how to achieve this?

Thanks.