Accessing fields of a deep structure

Hi

I have a deep ( complex ) structure whose structure is as follows :

A ( Structure )

B ( A field of Structure A , B itself is a structure too )

C ( is a field of Structure B , contains two fields D & E )

D & E are fields of structure C and are table types

Now in the OO context, I am trying to implement a method - the above deep structure is an import parameter to the method and I am trying to access the fields of table types D& E .

To access the fields of D & E, I try to go like - A-B-C-D-fieldname - I get an error in the OO context - saying that D is not recognized...

Any idea how do I access the fields on the tabletype given above within this deep structure ? Is this something specific to the OO context ??

Thank you in advance for your time.