DOCBOOK-APPS: Can I override a element of book-titlepage-recto-mode?

Hi,

Can I override an element of (mode book-titlepage-recto-mode ...) from 
dbttlpg.dsl, or do I have to override the whole lot?

Regards
-------
Richard Sharpe, , LPIC1
www.samba.org, www.ethereal.com, SAMS Teach Yourself Samba
in 24 Hours, Special Edition, Using Samba