If it's sufficient to have the coundown timer on a HTML-Page inside a custom-Item you could use a little Javascript inside the page.
Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title></title>
<meta name="author" content="stef">

<script type="text/javascript">
sec=60;
min=2;
function count()
{

sec--;
document.test.tmp.value=min;
document.test.tmp1.value=sec;

if(sec>0)
{
setTimeout('count()',1000);
}
else
{
if(min>0)
{
min--;
sec=60;
setTimeout('count()',1000);
}
else
{
alert('finish');
}
}

}

</script>
</head>
<body text="#000000" bgcolor="#FFFFFF" link="#FF0000" alink="#FF0000" vlink="#FF0000">
<form method="post" name="test">
<input type="text" name="tmp" readonly /> minutes and <input type="text" name="tmp1" readonly/> seconds to go<br />
<input type="button" name="varname" value="Continue" onclick="count()">
</form>
</body>
</html>
This will start the countdown after clicking the Continue-Button.
If you wish to start the countdown automatically just replace

<body text="#000000" bgcolor="#FFFFFF" link="#FF0000" alink="#FF0000" vlink="#FF0000">
with

<body text="#000000" bgcolor="#FFFFFF" link="#FF0000" alink="#FF0000" vlink="#FF0000" onload="count()">
And if you wish to proceed to the next item right after the countdown finished
replace

alert('finish');
with

document.test.submit();
To set the time just edit the line
min=2;
Don't change
sec=60;
unless you want less then a minute.
of course you can implement this code in every HTML-Site you want and place the Counters everywhere.

That's it

Regards
stef