problem with throw new soapexception

[aquadry@tps.corp.fr]

I use client that invoke dynamically web method (by reflexion), everything is
well, but not when the web method throws a webexception... client receives a
runtime exception

MethodInfo mi;
Object res;

try
{
res = mi[indice].Invoke(obj,arg Values);
}
catch (SoapException se)
{
MessageBox.Show ("Détail du message d'erreur:\n" + se.Message + se.StackTrace);
}

the client receives this message error:
An unhandled exception of type 'System.Reflect ion.TargetInvoc ationException'
occurred in mscorlib.dll
Additional information: Une exception a été levée par la cible d'un appel.

welcome to any help and thanks a lot.