[Webtest] xpath attribute escaping

[Thomas Colin de Verdière]

Hello,
in my page i have a button with a title attribute that contains a ' i 
would like to verify the text of the button
using xpath but i can't escape the ', i put a \ but it didn't work :
<verifyXPath description="check text and title for key F3"   
xpath="//button[@class='kb' and @title='my\'button']"
   text="F3" />
Thanks,
Thomas