Linking Nintex To-Do Task to existing Sharepoint custom list

Hello,

I have created a Sharepoint List (the template was "Import Spreadsheet")(at the top level of the page) and imported data from another page for testing a task management and workflow example.  The system works best when I create To-Do task inside of my workflow but I cannot figure out how to link my existing list (which is not a "Task" template list but a custom list) to the Nintex-created tasks.

I read that the default Task List name can be changed in the Central Admin settings but that still recreates the list initially rather than adding to the list of test task that I have already creaed (like 200 tasks). 

The workflow is started on an InfoPath form document library and I am using SharePoint/ Nintex Workflow 2010

Has anyone found a fix/workaround for this before?

Thanks in advance!