Setting Parameters for PlainTalk Speech

[Mac Dude]

First off, Thanks to both Jeanne and Dave Cragg for help with creating 
a folder on an FTP server!

Now, I realize this is really an AppleScript question, but i tried an 
AS mail list and got nothing, so since I know there's a knowledgeable 
bunch here...

Under Mac OS 9 I used to be able to set the Rate, Pitch and Modulation 
of a voice by embedding some simple commands ("[[rate <rate>]]", 
"[[pBas <pitch>]]", and "[[pMod <modulation>]]"), the latter 2 no 
longer seem to work under OS X, only the rate command works.  Can 
anyone tell me how to control the voice settings?