Thank you Will for your answer.
I know that. And i ve already tried with (PDF/X1) but the problem still remains.
And also for the margin (without the pdf virtual printer) i cannot operate on them...
I need to create a CMYK file from excel that allows me to "isolate" the black.
When i open the file in Acrobat and i select the black (to make a test), some gray color stil remains under the words!
This is my problem.