Question about cord blood donation... (The actual collection process!)?

We've made arrangements to have our baby's cord blood donated, and have already received the kit in the mail & everything. (I'm 35 weeks) I was wondering, when they do the collection of the cord blood, do they do it before the cord is cut, or after the cord is cut? I was hoping to let the umbilical cord stop pulsating before having it cut - Is this out the question when collecting cord blood? It's fine with me if I can't have it that way now, I already have the kit and everything, I was just wondering how it was all done!