Dynamic text on Activity indicator

is it possible to dynamically change the message in an activity indicator or do i need to add 2 on the same controller/view? right now, the 2nd AI message in the activation function is showing the first message.

coupon.xml

<Alloy>
    <Window id="window" class="container">
        <ActivityIndicator id="activityIndicator"/>
    </Window>
</Alloy>

if (uid > 0) {
    $.activityIndicator.message = L("loading_coupons_activity");
    $.activityIndicator.show();
}
.
.
function deactivation(){
    // doesnt emtpy -> $.activityIndicator.message = "";    
    $.activityIndicator.message = L("deactivating_coupons_activity"); //shows the loading_coupons_activity string
    $.activityIndicator.show();
}