Hi,
I am working on an extension of GoogleMapSelectableField, which manages this in a DataObject.
Currently it is so that it establishes a $has_one-relationship and thus receives a new tab. This also works great, but will not save the data.
Here are parts of the codes:

Page with Location:

class geoPage extends Page
{ …
	static $has_one = array(
		'Location' => 'Location'
	);
	…
	public function getCMSFields() 
	{ …
		$location = $this->Location();
		$fields->addFieldsToTab("Root.Content.Location", $location->getCMSFields() );
	}
}

Location DataObject:

class Location extends DataObject 
{
	function getCMSFields()
	{
		$fields = parent::getCMSFields();
		$fields = $this->scaffoldFormFields(array(
			'fieldClasses' => array(
				'Lat'							=> 'HiddenField'
				,'Lng'						=> 'HiddenField'
				,'Zoom'						=> 'HiddenField'
				,'FormatedAddress'				=> 'GoogleMapSelectableField'
				…
			)
		));
		return $fields;
	}

When I mount it so I also receive among my fields, a dropdown box with all geoPages.
But I get no connection between the Page and the Location.

I hope you can help me
Jörn

I forgot: I use silverstripe 2.4 beta

Edit: add Image & beta info