I don't want to mess with the ViewCache stuff in this version. I think it's too big of a change at this point. I'm also waiting to find out information about future WP7 versions and what its runtime and BCL will support with the hopes that we can have a
more consistent API across all platforms.
Sorry for not responding on that! I decided not to implement that because the OOTB converter is being used for the WPF version and it doesn't behave that way. So it's in order to maintain compat between WPF and SL versions without adding unnecessary code
to WPF. You can however change the default converter in the convention manager as well as change the converter conventions in order to get whatever behavior you want.