Bon avant que je dis des bêtise voici ce que j'ais dans le template system_siteclosed.html
<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Strict//EN' '
http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd'><html xmlns="
http://www.w3.org/1999/xhtml" xml:lang="<{$xoops_langcode}>" lang="<{$xoops_langcode}>">
<head>
<!-- Theme name -->
<{assign var=theme_name value=$xoTheme->folderName}>
<!-- Directory html files -->
<{assign var=theme_name value=$xoTheme->folderName|cat:'/xotpl'}>
<!-- Title, metas, style sheet ... -->
<{includeq file="$theme_name/xohead.html"}>
</head>
<body>
<div id="xo-canvas" class="<{$xoops_dirname}>">
<!-- Start header -->
<{includeq file="$theme_name/xoheader.html"}>
<!-- Navigation Menu -->
<ul id="xo-globalnav">
<li></li>
</ul>
<!-- End header -->
<!-- Star Site Closed form -->
<div id="xo-siteclosed">
<!-- Star message -->
<{$lang_siteclosemsg}>
<!-- End message -->
<form action="<{$xoAppUrl user.php}>" method="post">
<p>
<!-- User Login title -->
<strong><{$lang_login}></strong>
<!-- User name -->
<label for="uname"><{$lang_username}></label><input type="text" id="uname" name="uname" size="12" value="" />
<br />
<!-- Password -->
<label for="pass"><{$lang_password}></label><input type="password" id="pass" name="pass" size="12" />
<br />
<!-- Submit button -->
<input type="hidden" name="xoops_redirect" value="<{$xoops_requesturi}>" />
<input type="hidden" name="xoops_login" value="1" />
<input type="submit" value="<{$lang_login}>" />
</p>
</form>
</div>
<!-- End Site Closed form -->
<!-- Start footer -->
<{includeq file="$theme_name/xofooter.html"}>
<!-- end Footer -->
</div>
</body>
</html>