XYFX applied to Audio Track

Hi All,
I've been going through the manual, and this forum to find an answer, but haven't come across it yet. I have what I believe to be a pretty simple workflow I want to complete, but its proving to be a more difficult than I had thought.

Desired task.
Run the XYFX phaser effect over an audio track.

Steps taken.
1-Send the desired audio track to a submix
2-Insert the XYFX to the submix effect stack
3-Play with the effect a few times while workflow is in "Read" mode (verify that this does indeed add the effect)
4-Switch the work flow to "Write" mode
5- Press the screen in XYFX screen and lay down the effect.

I can hear that the effect goes through in real time. I can see that the effect has been inserted into the effect stack. However, on subsequent play backs I do not here the effect.
I've tried so many different combo's of work flow, overdub, and record, and yet the effect does not repeat on the audio track after the initial input.

I'm sure many folks are using XYFX on audio tracks, so what is it I'm missing.

And for a FYI I've used the XYFX on plenty of midi tracks, so I'm pretty confident using the functionality.
Any help appreciated.