How to fix Text-to-Speech pronunciation errors?

[Mettiu]

I think that the new voices found in Lion are impressive and there are a couple of them that I use regularly to have texts read.

However, there are some pronunciation errors I would like to fix (like the pronunciation of date written in Roman numbers), yet I have not being able to find the way to. I have found the advice to add new pronunciation rules in VoiceOver Utility, but that works only with VoiceOver and not with Text-To-Speech.

Does anybody know how to specify the pronunciation for certain words?

 

Thanks in advance!