6 speed wont go to reverse

http://www.toyotanation.com/forum/134-6th-generation-1988-1992/174725-fitting-c160-6-speed-into-ae92.html :help:: i modified the shifter and stilll wont go to reverse. any reason why it wont go? when i try to run it on all the gears it could on go to 6 slots. i have shortshift btw. and i...