I don't do any work with the encoder, so I'm REALLY not the person to ask.
You might try posting the question on the
microsoft.public.windowsmedia.encoder or
microsoft.public.windowsmedia.encoder.optimizations newgroup. I think
you're more likely to get help there. This newsgroup focuses on Windows
Media Devices which are things like WMA players, Portable Media Center, and
Windows Media Connect devices.
Sorry I couldn't be more help,

Signature
Alan Ludwig
Software Design Engineer
Windows Media Devices Group
This posting is provided "AS IS" with no warranties, and confers no rights.