Fallout: New Vegas "I put a spell on you" quest help?

I have discovered who the spy was, killed, him, got the code, reported to Hsu. who then told me to hurry to the monorail. i then disarmed the bomb, and was prompted to return to Hsu. when i return he asks "what happened?" but i am not given a line of dialogue that pertains to telling him the bomb has been defused. is there something i'm missing or have forgotten to do? the only thing its says under the quest section of my pip boy is "return to Hsu'