How to control "back" button

hi
i need to control the back button
in some decks to avoid back-navigation
actually, i have a card that asks
"remove item?: <yes> or <no>"
and i wish the user can't return the that card
when he accepted to "remove item"

to inhibit backward-navigation
i do the following
but this don't work

<wml>
<template>
<do type="prev">
<noop />
</do>
</template>
</wml>


do you know how to make it ?!
thanks ia