If you can't get a satisfactory solution here, consider posting to ActiveState's PDK mailing list.

Cheers,
Rob
Afterthought: Can you achieve success by creating a separate file ? ie, assuming your executable is named 'script.exe', create another file (in the same folder) called 'script.exe.manifest' that looks like this:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.
+0">
  <assemblyIdentity version="1.0.0.0"
     processorArchitecture="X86"
     name="script.exe"
     type="win32"/>

  <!-- Identify the application security requirements. -->
  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
    <security>
      <requestedPrivileges>
        <requestedExecutionLevel
          level="asInvoker"
          uiAccess="false"/>
        </requestedPrivileges>
       </security>
  </trustInfo>
</assembly>
[download]

That worked for me in relation to a 'patch.exe' that I copied across from a Windows 2000 box. (The excutable wouldn't run until I created 'patch.exe.manifest')