"He called on Mary to grace mankind with her spiritual presence"
She's not omnipresent is she?
That was my question when I read this also. If that is not what is believed, how would the Pope's comment make any sense?
Perhaps I misunderstood his words, but I didn't conclude that was his meaning.
Catholic teaching on this matter can be found, among other places, here: http://www.catholic.net/rcc/Periodicals/Faith/0910-96/articl10.html
Mary has told one of her,servants,St. Catherine Sienna,that she is the channel through which graces flow from ..and said,"those who ask graces of me, I shall grant".
God gave Mary this "power" to be helper of those who call on her,as a Mother,to help them! Simple as all that ! That is what the Pope means.
As we(hopefully) shall be after the general Resurrection.