It is now possible to look at/print or send a print-out that shows the internal text on a treatment.

Normally it's the EXTERNAL text on a treatment which is shown on a invoice

This is how the print normally looks - showing the external text when invoicing.

Now it is possible to choose a print format that can show the internal text instead. These formats are named with VTF.
Rightclick on the treatment, choose print and choose the VTF format

Now the print shows the internal text