I am writing a plugin. I want to add page of this plugin to the user template as sub navigation. (see below)

Also, I the url of this page should look something like this.
'url' => qa_path_html('user/' . $handle . '/somepluginpage')
I tried this coded, but it wont work.
function qa_user_sub_navigation($handle, $selected, $ismyuser = false) {
$navigation = qa_user_sub_navigation_base($handle, $selected, $ismyuser = false);
$nav_pluginpage= array('somepluginpage' => array(
'label' => 'Some Plugin Page',
'url' => qa_path_html('user/' . $handle . '/somepluginpage'),
)
);
$navigation = array_merger($navigation, $nav_pluginpage);
}
And I tried this one as well, it also does not work.
function doctype() {
qa_html_theme_base::doctype();
global $qa_request;
// adds subnavigation
if((bool)qa_opt('someplugin_enabled') && ($qa_request == 'somepluginpage' || $qa_request == 'user' || $qa_request == 'account' || $qa_request == 'favorites' || $qa_request == 'user-wall' || $qa_request == 'user-activity' || $qa_request == 'user-questions' || $qa_request == 'user-answers' || $qa_request == 'messages') && qa_get_logged_in_level() >= qa_opt('somepluginpage_level')) {
$this->content['navigation']['sub'] = array(
'somepluginpage' => array(
'label' => 'Some Plugin Page',
'url' => qa_path_html('somepluginpage'),
'selected' => ($qa_request == 'somepluginpage')
),
);
}
}