Nice. I did a mistake when i wrote 1080i or 1080p. This is the field mode like upper first, or in case of 1080p progressive. When i rendered it in Sony Vegas with 1440x1080 the video keep the profile of codec in level 3.1. When you render in 1920x1080 it upscale automatically to level 5.0. I think that this is the problem.
Ihave used another programs to sync my Ipad to PC but i had problems when i was to play it. The only way that i found to render a video in 1080p quality and just drag and drop to Ipad using Itunes, and that have no problem when i was play it was this way. Make a test with 1min video and reply after to see if it works for you. :D
Sorry by my English, its not my native speaker.