Here is another way to put static links to Magento catalog menu.
First, create static page, assign some url key to it, for example, "my-test-page".
Go to /app/code/core/Mage/Catalog/Block, copy file Navigation.php to /app/code/local/Mage/Catalog/Block, now you able to edit it without any worries about the possibility of loosing your changes with Magento upgrade.
Open file Navigation.php at line 265 (magento 1.4) function _renderCategoryMenuItemHtml(...), change code:
$htmlLi .= '>';
$html[] = $htmlLi;
$html[] = '<a href="'.$this->getCategoryUrl($category).'"'.$linkClass.'>';
$html[] = '<span>' . $this->escapeHtml($category->getName()) . '</span>';
$html[] = '</a>';
to that:
$htmlLi .= '>';
$html[] = $htmlLi;
if(preg_match('/\/static-/', $this->getCategoryUrl($category))) {
$link_url = str_replace("static-", "", $this->getCategoryUrl($category));
} else {
$link_url = $this->getCategoryUrl($category);
}
$html[] = '<a href="'.$link_url.'"'.$linkClass.'>';
$html[] = '<span>' . $this->escapeHtml($category->getName()) . '</span>';
$html[] = '</a>';
Now go to Categories management, edit category, change URL key to that: "static-my-test-page" and uncheck "Create Permanent Redirect for old URL" check-box. After saving category you will have link to my-test-page at top categories menu in Magento.
So after all that changes you can convert category link to static page link by adding prefix "static-" to category URL key.