Setting dynamic attribute

Hello,

I'm wondering if it is possible to sett adribute for the widget from dataprovider for example:

    <screenSecondMenu>
        @{menuName}
        <menupopup>
    <_renderer>
        <![CDATA[
                <menuitem onAction='@{onAction}'>
                    @{text}
                </menuitem>
        ]]>
    </_renderer>
    <_items>@{menuItem}</_items>
        </menupopup>
    </screenSecondMenu>

what I want is to set onAction atribute, but I only managed to do it so using $ thus it's not possible to change later on.

do I miss something or this is not possible?

Caution that dynamics properties (${...} and @{...}) couldn't be defined in attribute="value" syntax. You must use <_attribute>value</_attribute> syntax (see Tutorial 5).