Mysterious IMPLIB.exe silent failure with 64-bit DLL as input.

Hi everyone, I wonder if someone can help me?

I am trying to use the IMPLIB tool in the simplest possible usage case. I just want to transform a DLL into a corresponding import library. This is pretty straightforward and works with a 32 bit DLL as input just as expected ie:

implib.exe ftd2xxtest.lib ftd2xx.dll

The file that results, ftd2xxtest.lib looks sensible and has a non-zero filesize and works when I incorporate it within builds. So far so good!

However, in another app I also need to transform some 64 bit DLLs too into 64 bit import libraries. I tried to do this in exactly the same way as the 32-bit case ie

implib.exe ftd2xx64test.lib ftd2xx64.dll

Upon further investigation though ftd2xx64test.lib output from implib has a 0-byte filesize, so is not useful! So IMPLIB fails silently without errors when passed 64-bit DLL as input.

I looked for a 64-bit version of the tool ie IMPLIB64.exe in the bin64 directory of my RadStudio install but couldn't see this! What I am I doing wrong here, how can I obtain my 64-bit import library from my DLL? Do I need to pass some extra command-line switches to IMPLIB.exe?