Thanks for instant reply and i am sorry that i am replying too late
cat answers.txt|install.bin works...
I created a dummy script that asks for some options like name surname and i gave those values in answers.txt file and it worked properly.
But i am afraid that will it work on the actual installer? As i dont know that how they have been written...and i dont want to take any risk because environment is very crucial... if something got wrong they will kill me for my initiative