When you are developing a user-defined node, you must create the user interface representation of the node in the workbench.
If you have a plug-in node from Version 2.1, you must migrate the node to Version 6.0 using the mqsimigratemsgflows command, as described in Migrating a message flow, then follow the instructions in the steps listed above.
For user-defined parsers, just install the compiled .lil file. You do not manipulate parsers from within the workbench and therefore you do not create a user interface representation of user-defined parsers.