Horse trailer loading problems! Please help!?

When we first got my horse, Hoo, in october of '09 and when we picked him up he loaded fine (into a 4 horse slant goose neck trailer) well it was my trainers trailer so obviously we had to buy our own, we bought a 2 horse slant load bumper pool, he did fine loading up when we loaded him the first time in the new trailer, and about 4-5 maybe more (i cant quite remember) times. Recently he started balking. He will get in then back straight out (so you don't have time to close the dividing bar or tie him, and if i time him he might hurt himself again) The lady who owns the place we board him worked with him for a week, but he kept doing it, up to where it would take us 2-3 hours to load him (and when barrel races end at 11 and 12 its no fun to have to sit there for 2 more hours trying to load him!) We tried the "tough love" approach. We put a rope halter on him (with the connected lead line) and opened all the windows (put the bars down and everything) then we took the lead line through the window and looped it to the tie ring on the outside and had a barn hand hold it. Well long story short it ended up costing us $350 after he tore the tie ring off the side of the trailer and sliced the bridge of his nose on the top of the trailer. Well since hes been having problems as soon as he got the staples removed from his nose we started working them on the trailer. Now he puts his two front feet in and goes no farther! food doesn't work, pulling doesn't work, we believe he was a abused when he was young because hes scared of men kinda (gets the wild eye when they're around) and is terrified of whips. Please help meee!! i have a rodeo this weekend, and i plan to work with him everyday, but i need suggestions, ive lost hope in him!