DOCBOOK: writing man pages with refentry element

Hi,

I am trying to write a man page with the refentry element. I have a
question on how to write the description of the optional parameters 
for example 

-a this option enables bla bla
-b enables this and that

I though of using variablelist or table but I am not sure which one
suits inuse for man pages. Any suggestions will be helpfull



-- 
Togan Muftuoglu