Readonly attribute for dateTimePicker

[Sergio Rossini]

I'm using Struts 2.1.6 and datetimepicker tag.
Everything is fine, but I need to set the attribute readOnly for the input for date.
The tag datetimepicker does not have this attribute and I am not getting the input because it is load through ajax method of dojo.
The code

 
<sx:datetimepicker name="dateBirth" id="dateBirth" displayFormat="dd/MM/yyyy" />

turns into

<span style="white-space: nowrap;" id="dateBirth">
<input type="hidden" dojoattachpoint="valueNode" value="2009-07-08T00:00:00-03:00" name="dateBirth"/>
<input type="text" autocomplete="off" dojoattachpoint="inputNode" style="vertical-align: middle; width: 7em;" value="" name="dojo.dateBirth"/>
<img style="vertical-align: middle; cursor: pointer;" dojoattachpoint="buttonNode" dojoattachevent="onclick:onIconClick" alt="Select a date" src="/Geraminas/struts/dojo/src/widget/templates/images/dateIcon.gif"/>
</span>

The attributes onkeypress or onfocus at datetimepicker could help with some javascript but they gone in final html.
I've searched for the web but I can't find anything conclusive.
Anyone for help?