Nothing new has appeared in the S12 manual .PDF - so I guess it's safe to assume that the feature hasn't appeared.
I've given up holding my breath on this one and use PgcEdit; it's really easy to set up which are the "adjacent" buttons when navigating with the arrow keys. Ad while you're in PgcEdit you can also fix other navigation issues such as "return to menu" markers that won't jump back to the right menu 
Regards,
Richard