DOCBOOK-APPS: Controlling hyphenation

Hi,

How can I control the way hyphenation occurs
like I want to have a minimum of 3 characters before it is hyphenated
and the minimum number of characters after hyphenation should be 2. 

Like this is already done for me in FOP but in XEP I have to find a way
to tell it. I could not find a parameter where I can add these numbers
or is there one and I missed it ?

Thanks
-- 

Togan Muftuoglu