1. Acrobat (but not Reader) has an SDK which would allow you to set
2. I don't know what you would want to achieve by putting backspaces
in the keywords, but it seems to me that it probably wouldn't work.
PDF's text handling model doesn't recognise backspaces as being any
more than an invalid character.
Ok. Thanks for your answer.
About the Adobe SDK, I won't use it because I'm creating a scheduled task in VBScript which converts files, and in depends of the case, edit their properties or not. And because the pieces of information I want to put in the file properties are extract from an XML file, I wanted to keep at least some structure, and not simply writing them one next another.