Hi Mike,
This sounds more like an issue with WordPress than with BuddyPress or CBOX.
On single site, the “Add New User” screen looks like this:
http://codex.wordpress.org/Users_Add_New_Screen
Did you click on the “Send Password” checkbox when you were creating your user? If so, the new user should receive a generic “Your username and password” email with the site link.
On multisite, the “Add New User” screen looks like this:
http://i.imgur.com/kPlgT.png
If you fill out this form, the new user gets the same email as described above.
I just tested this in both single and multisite and I was able to verify this.