date formatting

hello,

in my template I have an input field which contains the date a shelf 
expires.

<input type="text" name="{$shelf_expire.name}" 
value="{$shelf_expire_value}" class="bg{$shelf_expire.farbe}" 
size="{$shelf_expire.breite}" {$shelf_expire.readstatus} />

Given the value for $shelf_expire_value is 2099-12-31 the template 
returns just that.


If I use:
value="{$shelf_expire_value|date_format:'%d.%m.%Y'}" instead of 
value="{$shelf_expire_value}" I get the result: 04.10.2007, which is 
today's date...

Is date_format only working with a certain type (format) of string? How 
can I get the desired output of: 31.12.2099?

Thanks in advance,
Peggy