aqui lo que sale mal son el selected ya que lo quiero hacer multiple

<%@ page contentType="text/html; charset=UTF-8"%>
<%@taglib uri="/WEB-INF/struts-bean.tld" prefix="bean"%>
<% String ctxPath = request.getContextPath() + "/altiuspar/";%>
<tr>
  <td width="33" rowspan="2" valign="top">
    <img src="<%=ctxPath%>images/lcolbox_header6c.gif" height="200" alt=""/>
  </td>
  <td colspan="97">
    <div class="radiosButtons">
      <table width="600" border="0">
        <tr>
          <td colspan="4">
            <h4><bean:message key="mifune.filter.content.hotel"/></h4>
          </td>
        </tr>
        <tr>
          <td>
            <input id="cad" name="PTNTIPENC" type="radio" checked="checked" value="0" class="radio" onclick="CambiarContenido(this);" />
            <label><bean:message key="mifune.filter.chain"/></label>
          </td>
          <td>
            <input id="marca" type="radio" name="PTNTIPENC" class="radio" value="1" onclick="CambiarContenido(this);">
            <label><bean:message key="mifune.filter.brand"/></label>
          </td>
          <td>
            <input id="hotel" type="radio" name="PTNTIPENC" class="radio" value="3" onclick="CambiarContenido(this);">
            <label><bean:message key="mifune.filter.hotel"/></label>
          </td>
        </tr>
      </table>
    </div>
  </td>
</tr>
<tr>
  <td height="163" colspan="3">
    <div class="radiosButtons">
      <table width="680" border="0" cellspacing="2">
        <tr>
          <td width="224" align="center">
            <p><bean:message key="mifune.filter.select.left"/></p>
            <select id="CB1" name="PTAHOTELA" size="5" multiple style="width:200px" disabled="disabled" ondblclick="javascript:AgregarSeleccion();"></select>
          </td>
          <td width="189" align="center">
            <input name="ADD" value="<bean:message key="mifune.button.add"/>" type="button" class="button sub" onclick="javascript:AgregarSeleccion();"/>
            <br><br>
            <input name="REM" value="<bean:message key="mifune.button.rem"/>" type="button" class="button sub" onclick="javascript:RegresarSeleccion();"/>
          </td>
          <td width="226" align="center">
            <p><bean:message key="mifune.filter.select.right"/></p>
            <select id="CB2" name="PTAHOTELB" size="5" multiple style="width:200px" disabled="disabled" ondblclick="javascript:RegresarSeleccion();"></select>
          </td>
        </tr>
        <tr>
          <td colspan="3" align="left">
            <h1 class="title2"><img src="<%=ctxPath%>images/icon_info.gif" alt="" /><bean:message key="mifune.filter.hotel.warning"/></h1>
          </td>
        </tr>
      </table>
    </div>
  </td>
</tr>
<select id="CB3" name="PTAHOTEL" size="1" multiple style="visibility:hidden"></select>
<input type="hidden" id="enc" name="PTAHOTENC" value=""/>
<input type="hidden" name="PTAFOOT" value="<bean:message key="mifune.filter.hotel.warning"/>"/>