Custom fields with remote protocol

I am trying to add and retrieve custom field entries on images using the gallery remote protocol. When I make a 'fetch-album-images' request, the result does not seem to include any of the custom field data that I have on the images. Similarly, when I make an 'add-item' request, it does not seem to add the extrafield. Is this particular to G1? If so, is there an alternative way for me to extract the custom field data from items using the remote protocol?