plugins/sys/templates/admin/confirm_reg/main.stpl
<div class="editform">
<form method="post" action="{form_action}">
<p class="first">
<label>{t(Enter login to confirm)}:</label>
<input type="text" name="login" size="35" maxlength="35" />
</p>
<div class="button_div">
<input type="submit" value=" {t(Submit)} " />
</div>
</form>
</div>