Set nodeId in task of order business process

Hi I'd like to setup the nodeId in tasks of my order business process. Does anyone tried to do something like this already? I know that each steps in business process is a TaskModel which provide the nodeId attribute but in XML definition of business process, we don't create TaskModel but Action so i can't find where to put the nodeID value :/

Currently nodeId is empty when running business process and i'm guessing that's why it doesn't work in my clustered environment (it works locally). So any help will be appreciated. :)

Thanks!