chapter title styling

Hi all,

I'm currently porting a document from memoir to scrbook. There is one thing that is still not quite clear to me regarding chapter titles. memoir allows me to control the following regions in a chapter title:

XXXXXXXXXX
Chapter 3
YYYYYYYYYY
The Title
ZZZZZZZZZZ

with the following macros:

\chapterheadstart (for XXXXXXXXXX)
\afterchapternum (for YYYYYYYYYY)
\afterchaptertitle (for ZZZZZZZZZZ)

From the KOMA-script documentation I figured out the following:

\renewcommand*{\chapterformat}{...}

That works for the XXXXXXXXXX and YYYYYYYYYY but not ZZZZZZZZZZ. I'm personally not comfortable with redefining \makechapterhead or other internal macros. Is there a way to do this?