can we add information to the svn error message?

Hi all,

until now our system (our repository) is storing valid docbook files and
rejecting non-valid docbook files.
We have already done a pre-commit to allow us to differenciate between
them .... but
but we want to add some information about the error in the message
thrown to the user, is that possible?

Many thanks and a happy new year. luis.

-- 
Luis Cañas Díaz <lcanas@gsyc.escet.urjc.es>
GSyC - Edukalibre              
Universidad Rey J.Carlos       0>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~//)~~~~~~~~~~~
web: http://gsyc.escet.urjc.es/~lcanas