Due to one of Pascal's structure limitations, and my slight knowledge of assembly, the source given here will not work correctly if compiled. It is available for educational purposes only. Specifically, when the FKEY can't find the SitC resource, it says so. But this is hard coded as a pascal string. However, the scrap doesn't want the length byte. So with ResEdit, I took out the length byte in the compiled code, and updated the assembly module to know the correct litterals length.
If you don't know what that means, don't worry. Just don't compile this source and expect to get the same FKEY.