I'm trying to write some disk images without using ADT Pro (because I'm lazy) and I'm having a hell of a time.

I've downloaded it from here. I've also downloaded ProTYPE 1.1.
I've followed the instructions to run BINSCII and dropped it into ProTYPE, then using appleshare I sent it to my IIgs however I still can't run it no matter how carefully I try to handle the file. It's always a File Type Mismatch. Without BINSCII I can't extract the disk utility or even the disk images themselves. What's the secret?