its at the cost of any gameshared dlc - if (like me) you lost your friends password.. your screwed. this method makes you have no limits, pretty much. BUT your gonna have to make sure that:
a) you have used no DLC pieces
b) your not merging DLC pieces
so i would mess with it and plan out what your gonna do, its a lot easier and works a lot more ways but theres this big cost right. <--

unfortunately i have no clue how to do this for xbox as im a rich snob.. jk

ps3 menu --> GAME DATA utility --> Skate 3 DLC (Triangle) --> Delete --> play game --> DONT INSTALL UPDATE.. install game data --> make park --> put prop on a pad at desired angle --> make another pad and simply drag it down into the prop from above the prop, i think it has to be bigger than the prop im not sure

well worth the 5 mins if you ask me, make sure you know what you want to make and build your parks around it. sorry xbox people.