First of all, I am newbee to xmp implementation with exiftool so please understand me... I need a help. I would like to use the `keyword` xmp field of pdf document to write 3 to 4 additionnal informations with exiftool. i'd like to write each information on a new line of this same field. When I do that with exiftool, i have got an error on updating the file. I can only write a one line information. Now from Acrobat, i've tried the same thing. I've written these separate informations, each on a a different line into the `keyword` field, then saved the document. The metadata seems on a good format to accept the carriage return information. I've looked into the resulting binary pdf file in non-Hex mode and watched to the metadata information, seeking for my `keyword` field representation. It appears like that :

Can anyone help me to understand how to reproduce a such implementation from a command line use of exiftool or simply how to implement a carriage return information on a field ? Thanx in advance ! :)