RichTextBox control does not recognize all RTF control codes

Question

Hi,

Does anyone know why doesn't the Richtextbox control recognize all
rtf control codes specified in RTF v1.6?

According to MSDN it should:
"For the RTF codes, see "rich text format (RTF) Specification, version..." - that's on the RichTextBox control documentation page.

I am specifically looking to control character spacing inside the control. The
codes \expnd and \expndtw do this successfully in Word, but they are
ignored by RichTextBox control. Note, they are also ignored by Worpad, which makes me think I'm out of luck on this one. Is there any hope of controling character spacing in RichTextBox control?

Thank you so much in advance!

-Alexei