Last Jan, when we did the Pirate/Princess Party, we used those tickets to enter the park. We got there about 6:00ish. We all had regular passes we could have used, but the CM at the turnstyle said to just use the party tickets. As soon as we got through the turnstyles, there was a CM giving out the wristbands, who also marked our party tickets to show they had been used.
Okay, so far so good. Well, we got to Space Mt about an hour later. Walked up to the FP machine, put in my pass, and it wouldn't work. Tried the next machine...still nothing. I was more than a bit irate. The CM asked me what I had used to enter the park. Duh...my party ticket!! CAn't use the AP if you didn't use it to get into the park. What a dummy. So...keep that in mind. Be sure to use whatever park media you used for park entrance at the FP machines. That was something I just didn't think about.