What does graduated mean in the Netherlands? I have been admitted to a Master in the Netherlands, but my diploma will be awarded after the enroloment date there. However, the university says they can process my admission if I send them an official letter stating that "I have graduated", completed my course work, and that the diploma will be awarded later. 

In my country and university, the list of students that will receive the diploma is authorized by the Academic Council first and diplomas awarded later. When the list is issued, the Council gives a letter stating that you are graduating. I am not sure if such letter is the equivalent to what the Dutch University needs. Anyone at a Dutch university knows what they exactly want?

Edit: Official documments at my University are issued in Spanish, not in English, therefore I have to get the document translated by an official translator. Hereby, I want to the document to be sharp enough to avoid changes in sense or missinterpretations in any stage.
I'm Dutch and did my bachelor/master and PhD studies at a Dutch university (Utrecht), but can't claim to know exactly what they want; for that you'd really need to get in contact with the people at the university who are in charge of the admission procedure.

That said, I think they want an official confirmation that you passed all requirements necessary to get your degree, and so it seems that the council letter might be sufficient.