Note: Put the import action in a process and then use it in Informatica. Still facing the issue? try the below one.
I hope you are using Synchronization task to run an import action. If I understood correctly, your import action is within a model or Model to model import and doesn't involve any file upload. If that is the case, in Informatica you have to create a 'Dummy connection' as Source and Your model as 'Target'. To elaborate, to trigger any action in a model keep that model as Target connection and Source as 'Dummy connection'. So this Dummy connection could be anything, a flat file (Stored in the server) or Your external 3rd party system (Oracle,SAP,etc..) all you need is a Table with hearer. So once you set the connections, in field mapping map any header from source to the Target (which is your action). It should work. Please try and let me know in case of any concerns.
Re: Importing boolean from Informatica for List subset
Thank you @kavinkumar for your help with this matter. I was able to go around the problem by creating a model-to-model import and wrapping it in a Process action that I call from Informatica like you suggested.
This works well for what I am trying to do but it is slightly different from what I was inquiring about (I should have explained better). The import I created initially and documented in screenshot 1 is a file Import in Anaplan that I was trying to map in an Informatica Synchronization task. The idea with this task was to match multiple list items in Anaplan with Salesforce records (the source in the sync. task) and systematically make these part of a subset. In order to do that I have mapped the list items with the ids I have selected from SalesForce and wanted to create an expression in Informatica to include these items in the "Add_to_Hierarchy_" subset (cf. Screenshot 2). Because subsets are treated as booleans in Anaplan I figured I needed to create a "TRUE" expression but that did not work. There is an "Edit Types" button in the mapping screen in Informatica but it is not possible to select anything else other than string so I wonder whether it is even possible to import data in Anaplan directly as boolean (wchich would be necessary to update list subsets).