Geotargeting Page Posts with the Facebook API - php

Question

I'm trying to geotarget wall posts to my fan page using the Facebook PHP SDK.
The following snippet successfully posts a message to my wall, but the geotargeting isn't taking.
I'm new to programming and I've done my best to follow the documentation here but it's pretty sparse -- I'm not confident that my syntax is correct.
Any help would be very much appreciated.
//compiling the geotargeting parameters
$geoTarget = "{'cities':'Richmond,VA','regions':'Virginia','countries':'US'}";
//my arguments
$args = array(
'access_token' => $page_access_token,
'message' => "this is my message",
'targeting' => $geoTarget
);
//posts the message
$facebook->api("/$page_id/feed","post",$args);

Answer 1

The field is privacy in the Post table
The description field may contain a comma-separated lists of valid country, city and language if a Page's post targeting by location/language is specified.
http://developers.facebook.com/docs/reference/api/post/

Answer 2

To make this easier this is the bit you need http://developers.facebook.com/docs/reference/api/page/#targeting
this will give the info on how to target regions too.
http://developers.facebook.com/docs/reference/ads-api/get-autocomplete-data/
What you need to complete the targeting in the question would be:
The countries bit was right.
Virginia's region code is 51 (which you can find by searching _">https://graph.facebook.com/search?q=vi&type=adregion&match_country_code=true&country_list=US&access_token=_)
Richmond's city id is 2538983 (which you can find by searching _">https://graph.facebook.com/search?q=richmon&type=adcity&limit=150&access_token=_)
so the geotarget would be
$geoTarget = "{'cities':[2538983],'regions':[51],'countries':'US'}";