Saved fields empty when 3D window activates

I've created Text Fields and Check-boxes using LiveCycle Designer in my pdf template.

I create the 3D work in Reviewer, and use the template during Export to 3D.

Using 'Extend Features in Adobe Reader' the text entries, and filled in check-boxes can be saved with the pdf using Reader.

So far this is great!

The problem comes when the pdf is opened again and the 3D window is clicked to activate.

All the completed fields empty!

This is very bad!

Is there something I can do to stop the fields clearing on 3D activation?

thanks,

Ian