I need to copy functionality to the ASR cockpit

[Ronnn]

Hi, 

In the ASR (Advanced shipping and receiving) cockpit I want to add a button for wave picking. A similar button already exists in the send cockpit. Now, I've been able (with help from colleagues) to add the physical button, but I can't seem to manage to add the functionality from that other button. 
Here's the existing button:

Here's the new button that should react like the button above:

here's the technical details of the new button:

I have added 'COPY' to the button for testing purposes. When I press the + sign I see a list of commands that can be added to the button:

But how can I add this functionality from the button to be copied?

I've read about I might need to implement the feeder class? I think that might be this one:

Does any guru here can tell me if I'm on the right way and know where to go from here?

Many thanks & regards,

Ron.

[Ronnn]

-UPDATE- I managed in getting the new value in the table with assigned actions. Next step is to actually make the button work.. I did this by enhancing class /scmtms/cl_ui_tbi_tree, method get_definition. I suspect I might also need to edit the get_data method.