(In-App Chat Mobile):Instead of using System Users table, want to use Own Users table


I have created Mobile App using In-App Chat forge component, in that i have implemented LDAP login  functionality using the external user table and not the System -->Users table.

When user logs in into my application, i want to store the userid (of my external users table) in the session. how do i do that, because the function GetUserId() takes the userid from the Systems--> Users table, which i do not want to use.

The In-App Chat forge component works fully, by using System--> Users table. I want to use my own User Table and use throughout the In-App Chat. Is is possible