[Zope] Checkbox question!

[florian@fischer.tc]

First i have a HTML Formular:
-----------------------------
<table border="0" align="center" width="800" height="450" bgcolor="#999999">
  <tr bgcolor="#003366" align="left"> 
    <td height="1" valign="top" bgcolor="#999999">&nbsp; </td>
  </tr>
  <tr bgcolor="#CCCCCC" align="left"> 
    <td valign="top" bgcolor="#CCCCCC"> <p>&nbsp;</p>
      <form name="form1" method="post" action="arten_uebertragen">
        <table width="700" border="0" align="center">
          <tr bgcolor="#999999"> 
            <td colspan="2">Art</td>
            <td width="386">&nbsp;</td>
          </tr>
          <dtml-in get_arten_tabelle> 
          <tr>
            <td width="24"> 
<input name="id_art:list" type="checkbox" value="<dtml-var id_art_auswahl>">
            </td>
            <td width="276"><dtml-var id_art_auswahl>. <dtml-var 
gruppierung></td>
            <td>&nbsp;</td>
          </tr>
          </dtml-in> 
          <tr> 
            <td colspan="2" bgcolor="#999999">neue Art:</td>
            <td bgcolor="#999999"><dtml-in get_arten_max> 
              <input type="hidden" name="id_art" value="<dtml-var 
expr="id_art_max+1">
              "></dtml-in> <input type="text" name="gruppierung"> </td>
          </tr>
          <tr> 
            <td colspan="2"> 
<input name="Submit" type="submit" value="&auml;nderung &uuml;bernehmen"></td>
            <td>&nbsp;</td>
          </tr>
        </table>
      </form> </td>
  </tr>
</table>

Second the SQL File "arten_delete":
-----------------------------------
DELETE FROM arten_tabelle WHERE id_art=<dtml-sqlvar id_art type="int">;

and third the submit File to the SQL File:
------------------------------------------
 <dtml-in get_arten_tabelle> 
 
 <dtml-if expr="id_art[1]==id_art_auswahl">
  <dtml-call arten_delete>  
 </dtml-if>

 </dtml-in>

"arten_tabelle" returns a list of numbers in "id_art_auswahl".
How do I programm a routine...that interprets the Checkbox-returnlist of id_art 
to compare it with "id_art_auswahl"?

Thanks...Florian Fischer