I was able to get an answer from Fred Smith on the PSR Tutorial forum....here is the reply it might help others.

Assuming you have an existing registration for the song, and have a text file which contains the lyrics, do the following:

1. Load the registration (say R1).
2. Press Lyrics/Text
3. If "Text" is displayed in the lower left,
then press button 1
4. Press button 6, and navigate to your text file
5. Exit back to main screen.
6. Press Memory button
7. Ensure Text group is selected (this is the important step)
8. Press R1
9. Save the registration.