Using the restful interface with view models

[Erik de Hair]

Hi,

For some use case we have a Wicket wizard using Apache Isis view models 
where each step enriches the view model as returned by the previous step 
until it is ready to submit. I was trying to redo this using the restful 
interface but I can't figure out what's the objectId of the returned 
view model. I need that I to start the actions related to the next step.

So I have an action 
/objects/WbaAvailability/{objectId}/actions/startAccessOrderCopper/invoke where 
object WbaAvailability is a view model. An other action (executed 
before) returns a list of WbaAvailabilities. But how to use one of these 
and invoke the startAccessOrderCopper-action?

Thanks,
Erik