Hi Jason,
The class does exist where the code is trying to look for.
We finally figured out that the class didn't define a default constructor (without any parameter) "explicitly" and hence it was not getting instantiated. 
Anyway, now we are able to proceed further and overcome the initial exception.
the class looks like this:
However, the custom data sent from ECC ( visible under table parameter after execution of the BAPI) is not reflecting on the screen. I had debugged the Java code and found that the "NAME1" field always remains blank.
I also placed a break point in the parametrized constructor of the custom class, but the control never stopped there. Moreover, the "setName1" method of this class also doesn't get called.
I see that the default constructor of the custom class (without parameters) is called first, which subsequently calls the setProperties(x) method of the base class. irony is, here also, the control doesn't stop in the parametrized constructor of the base class and I don't see any other way in which setProperties() method of the base class can be called. I am attaching a screenshot of the decompiled equipment class for illustration purpose.
