Carriage Return in Autonumber Format?

Hello,

I've set up my Structured EDD with some Headings that have Autonumbering.  I'm wondering if there is any way to put a return between the number and the text?

In other words, can I make this:

Chapter 2: This is the Chapter Title

look like this:

Chapter 2:

This is the Chapter Title

As a secondary question, in my search for the answer to this question, I discovered the <r>. <r+>, <R>, etc. "building blocks".  I can't find them mentioned anywhere in the user manual or developing structured application manual.  Can anyone tell me exactly what their function is?

Thanks!