Here we go:
1. Run this action in Photoshop and keep in mind the original size of
the opened panorama:

2. When this message pops up, click to cancel the action..

3. This is the result from the action till this point (the grid is set
to 50%):

4.Turn canvas by 180 degrees:

5. Run PTRemap Plugin as shown below:

6. These settings under Prefs will generate and open an additional, remapped
file:

7. Settings for the remapping job:

8. This is the resulting remapped view, looking straight down:

9. Here a little bit more zoomed in:

10. Open a prepared Photoshop text file to fill in like this (for download
see on top):
11. Drag and drop the text file over the remapped pano until it fits well
as shown below:
(to transform the text hit ctrl+T)

12. The text layer should be on top and selected. Don't flatten it to
background nor reduce to one layer!
13. Run the Remap plugin again:
14. Settings to remap back to equirectangular projection (PSphere):
15. This is the remapped text without the pano as result from the remapping
process:
16. These are the values from the remapped text file:
17. Change the values to the original size of your panorama. Mine was
6000 x 3000 pixels:
18. Turn canvas by 180 degrees again:
19. Duplicate background to a layer and delete original background:

20. Delete the white colour by selecting it:
21. In this dialog pick the white colour and click OK
22.This is the selected white colour (You can do this also with the wizard
stick tool)
23. Delete the selection and
only the needed text will stay (yellow highlighted):
Save this file for further use with this Photoshop action and give it
a name which
includes the size of the file, really helpful!)
24. Now you are able to drag
and drop this file to the panorama by holding shift key
(It should fit exactly in the white area in the panorama picture):
