Why can't I import a .txt file to a PDF created in Livecycle Designer?

[jsplount]

I am trying to import data into a PDF, simple stuff like names and addresses. I've saved my spreadsheet as a tab delimited .txt file, but when i go to import data in the PDF, .txt files are not an option. Is there a setting in Livecycle or in Acrobat that I haven't found?

[George_Johnson]

That feature is intended for forms created with Acrobat, not LiveCycle Designer.

[jsplount]

Is there a way for me to import the data to a PDF created in LiveCycle designer?