WPAlchemy MediaAccess inserting media link in WP Editor instead of custom field in metabox

I'm currently working with WPAlchemy class to create a metabox in a custom post type (Events from EventEspresso plugin more precisely).

This metabox should be able to call the media uploader and insert images for some custom metas.

It works pretty well, i'm able to call the media uploader and persist data from textfields. But, after opening the media uploader, selecting the image and clicking on 'Insert to Post'. The image link goes to WP Editor textarea instead of my textfield in the custom metabox.

Thanks guys. Hope its clear enough and sorry for the probably not very well written english.