Just look at how this is being accomplished using the existing {CUSTOM_HEADER}-token: depending on whether your custom placerholder token is suppossed to come before the {GALLERY}-token of after it (think of the {GALLERY}-token as a placeholder for the actual coppermine content as well as a separator between pageheader and pagefooter), you'll have to edit the corresponding functions pageheader or pagefooter that reside in your theme.
Let's say that you want your custom token to appear before the {GALLERY}-token: edit themes/yourtheme/theme.php and findfunction pageheader($section, $meta = '')and modify as suggested below. If this function is not being defined in your custom theme, copy the default function from the sample theme. To do this, copy // Function for writing a pageheader
function pageheader($section, $meta = '')
{
global $CONFIG, $THEME_DIR;
global $template_header, $lang_charset, $lang_text_dir;
$custom_header = cpg_get_custom_include($CONFIG['custom_header_path']);
$charset = ($CONFIG['charset'] == 'language file') ? $lang_charset : $CONFIG['charset'];
header('P3P: CP="CAO DSP COR CURa ADMa DEVa OUR IND PHY ONL UNI COM NAV INT DEM PRE"');
header("Content-Type: text/html; charset=$charset");
user_save_profile();
$template_vars = array('{LANG_DIR}' => $lang_text_dir,
'{TITLE}' => $CONFIG['gallery_name'] . ' - ' . strip_tags(bb_decode($section)),
'{CHARSET}' => $charset,
'{META}' => $meta,
'{GAL_NAME}' => $CONFIG['gallery_name'],
'{GAL_DESCRIPTION}' => $CONFIG['gallery_description'],
'{SYS_MENU}' => theme_main_menu('sys_menu'),
'{SUB_MENU}' => theme_main_menu('sub_menu'),
'{ADMIN_MENU}' => theme_admin_mode_menu(),
'{CUSTOM_HEADER}' => $custom_header,
);
echo template_eval($template_header, $template_vars);
}from themes/sample/theme.php into a new line before?>of the file themes/yourtheme/theme.php
Then add the custom token's content definition: edit themes/yourtheme/theme.php, find $custom_header = cpg_get_custom_include($CONFIG['custom_header_path']);and add after it (into a new line) $yourCustomVarName = cpg_get_custom_include('/absolute/path/to/your/additional/custom/include_file.php');
Next, find '{CUSTOM_HEADER}' => $custom_header,and add after it (into a new line) '{YOUR_CUSTOM_TOKEN}' => $yourCustomVarName,
Finally, edit themes/yourtheme/template.html and add {YOUR_CUSTOM_TOKEN} somewhere before the {GALLERY}-token.