Macro for retaining EXIF data in CTP files

As I have started to use Photo-Paint more extensively for touching up my digital camera images, I have noticed that EXIF data is not retained in the CTP-format. It is there as long as I don't close the image (if I start with a jpeg and resave as CPT and export a new jpeg from there), but if the file is closed then EXIF data is gone.
Clearly the CPT-format has some potential of retaining this data, but is seems to be dropped on purpose.
Now, my question is if somebody has created a macro for this purpose or if someone gets some inspiration to make one - if it is possible at all.
Regards,
Lars