Sweetie
NoOrdinaryPrincess was not being nasty. I am afraid it is true. If Disney are aware you performing a ceremony in the MK, or indeed anywhere on property, there could be very serious consequences for you, perhaps including being banned from the property. It simply isn't worth the risk.
Have you researched other options for getting married on property? Weddings at the S/D, DTD and CSR are available for a more reasonable price and are all still there right in WDW.
Good luck, and if you have any other questions, I would be happy to answer them.