Make PDF Creator use Postscript fonts instead of Windows Truetype fonts

Great Application!

Could you please be so kind to help me with following problem?

On Windows 7 Ultimate x64 with PDFCreator 0.9.9 I have following problem with Ghostscript settings:

When I disable "Use Windows Fonts" it does not seem to have any effects.

Still Truetype fonts are used in the created PDF files. (Email printed from Thunderbird 3)

I also looked in the Windows registry key HKEY_CURRENT_USER\\Software\\PDFCreator\\Ghostscript o see if disabling "Use Windows fonts" would change anything there but couldn´t find the corresponding value there either.

What effect should disabling "Use Windows fonts" exactely have?
Can I add a registry setting myself to make use of that option?