Its not nessary to use that other hack, you can do this with builtin features.
MAke a new template called
custom_sudoku
use this code
HTML Code:
<html>
<head>
$headinclude
<title>$vboptions[bbtitle] - Sudoku</title>
</head>
<body>
$header
<br />
<table class="tborder" align="center" border="0" cellpadding="6" cellspacing="1">
<thead>
<tr>
<td class="tcat" colspan="2"><center>Sudoku</center>
</td>
</tr>
</thead>
<tr height="500">
<td align="center" class="alt1">
<IFRAME SRC = "http://www.free-sudokus.com/cgi/sudoku.cgi?affiliate=1" width="435" height="435" scrolling="no">
</IFRAME>
</td>
</tr>
<tr>
<td class="thead">Rules</td>
</tr>
<tr>
<td class="alt2">
<div style="font-weight: bold;">Short rules</div>
<div class="smallfont">It is necessary to fill the railing by using figures from 1 to 9. Necessarily only once in every line, column and square of 3 x 3.
</div>
<br />
<div style="font-weight: bold;">To resume the vocabulary of the guide</div>
<div class="smallfont">It is necessary to fill the railing by using 9 given symbols (Generally figures from 1 to 9, or letters indicated at the foot of the railing). Necessarily only once (but no more) on every line, column and region (or squared by 3 x 3).</div>
</tr>
<tr>
<td class="tfoot" colspan="2"><div class="smallfont"><B>Options:</B> <a href="$vboptions[bburl]"> Home</a> | <a href="$vboptions[bburl]/misc.php?do=page&template=sudoku">Delete Railing</a></div></td></tr></tbody>
</table>
$footer
</html>
the url is misc.php?do=page&template=sudoku