Get all lines from multiline textbox

Hi, I have multiline textbox with HtmlExtender control from AjaxControlToolkit in my Web Forms application. And I have troubles with getting all of the text from textbox including linebreaks. I have this code:
Dim text As String = txtText.Text.Replace(Environment.NewLine, "<br/>") But I get only first line of text everytime. So I set a breakpoint and discovered that value (text) of textbox is always the first line (image - http://1drv.ms/1fBmwZS).
What can I do with this, where is a problem? 
Thanks for answer.