Validating -moz-box-sizing
===

I am using box-sizing with vendor prefixes, like this:
http://www.w3schools.com/cssref/css3_pr_box-sizing.asp

...running it through the CSS validator:
http://jigsaw.w3.org/css-validator/

...and getting this error:
**Property -moz-box-sizing doesn't exist : border-box**

Is there a way to make it pass?

Many thanks.