That's NOT at all the way the muslims see it. Muslims believe that Issac was an usurper, that Abraham was actually about to sacrifice ishmael at "allahs command," and that the true lineage of Abraham actually descends through ishmael, rather than the Jewish and Christian accepted beliefs of Issac (then Jacob, then the sons, which beget the Tribes of Israel.
Since Christians and Jews descend from Issac the usurper, they're "unclean" and are to be subjugated.
Mark
That is how I understood it as well that since Ishmael was first born Isaac took his place in line.