Hi Joe, Thanks for your response previously.
Have tried various versions of your and other coding but for some reason only Cost Centre assignments can be added via coding.
Also tried with Custom Z Object assignments - during debugging I can see that all typecode values are correct but they are not being passed to the new instance "local".
I then tried moving the parameter (eleJVitem) values directly into the instance (local) as shown below and it seems to work now (for custom Z Object assignments)!!
I will have try something similar with the Project Task Reference at some point in the future
Jay