what error did u get while trying to burn the cd with the floppy image file ?? . try to make a floppy disk itself with the floppy image and then try to run nero using floppy as boot image . Did u check for an option called emulate floppy in nero ?????? try testing the options , with and without emulation . using a cdrw , if u dont wanna waste cdr . i think u can even test out bootable cds with virtual pc .
try this MKBISO found here : *www.terabyteunlimited.com/utilities.html