I've extended my SilverStripe installation with a user registration page. I've altered a BackURL variable to the links to the login and regsitry pages.

However, how can I include the BackURL in my altered login template to include a message that they can register for an account?

themes/mytheme/templates/Layout/Security_login.ss

$Content
Login below or <a href="{$BaseHref}register?BackURL={$BackURL}">register for an user account</a>.
$Form
<a href="{$BaseHref}register?BackURL={$BackURL}">Register for an user account</a>

The BackURL is added to the Form itself, but not to the 'register user account' links.

I've tried adding a CustomLoginForm, but the BackURL information isn't available in the Security_login.ss (as it will probably need to be added to the Controller but I can't find the Form Controller.

<?php
class CustomLoginForm extends MemberLoginForm {
	public function BackURL() {
		if(isset($_REQUEST['BackURL'])) {
			return $_REQUEST['BackURL'];
		} else {
			return Session::get('BackURL');
		}
	}
}

Any help would be appreciated.

I've used...

Security::set_default_login_dest('urlsegment');

to set a site wide login destination, does this help?

No, that's not what I meant. There is a login link on each page. After a visitors successfully logs in (or chooses the register option on the login page) I want them redirected back to the page on which they clicked the login link.

how about something like the following in Page::init()?

Session::set('BackURL',$this->Link());

Solution turned out to be quite simple, I've ended up putting the BackURL function in the Page_Controller so it can be included into the Security_login.ss template.

class Page_Controller extends ContentController {

	public function BackURL() {
		if(isset($_REQUEST['BackURL'])) {
			return $_REQUEST['BackURL'];
		} else {
			return Session::get('BackURL');
		}
	}
}