datepicker disabled highlight some days

datepicker disabled highlight some days

Hi I'm tryng to add class with  beforeShowDay: at some days in datepicker (all disabled) just to show unavailable date to visitors.
In attachment my complete html (just changed the extension)
When i look the result i see
<td class=" ui-datepicker-week-end ui-datepicker-unselectable ui-state-disabled undefined ">
    <span class="ui-state-default">
        1
    </span>
</td>
Why it dont apply my class gior-occ , someone can help me?
Thanks in advanced
L.