In OpenPlant Modeler CONNECT Edition, requirement is to create a new associated item using OpenPlant Project Administrator CONNECT Edition
In OpenPlant Modeler CONNECT Edition, creating a new pipeline shows default associated items as Unit Service & Plant Area, refer image as shown below.
Below wiki article explain the customizations to add a new associated item as FACILITY CODE.
If above problem still persists, then please create a Service Request and contact the Bentley Product Advantage group. Please include a list of all relevant details to get in depth analysis for a solution or workaround.