Custom Post Types in the BP Activity Stream

Hi: I'm building a MultiSite network using WP 3.2.1 and Buddypress 1.2.10. Does anyone know: Is there a relatively straightforward way to make a custom post type on one of my network blogs show up in the BP activity streams? Obviously, the standard "post" type does; I'm wondering if anyone knows how I can make a custom post type - let's say for sake of this discussion, a post type named "newtype" - show up in the BP activity streams as well. NB: I'm willing to hack core to do this (bad form, I know... -- My thanks in advance for your comments --