The AutoInsertHyperlink property is applicable only when typing hyperlinks in RadRichTextBox in real time.
In order to insert a hyperlink in a RadRichTextBox programmatically you need to specify this. The following sample code inserts a hyperlink in the document programmatically:
HyperlinkInfo info =
Target = HyperlinkTargets.Blank,
"Link to Google"
You could find more information on that topic in our online documentation
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.