SQL & PL/SQL

Hi,

I'm using 11gR2. It seems to be impossible writing a compound trigger including an exception handler. But I need one.
Code is

create or replace trigger testtrg
for delete or insert or update on BTK.AVALTYP compound trigger
anyerr exception;
pragma exception_init(anyerr, -20005);

before each row is
begin
  null;
  raise anyerr;
  exception
    when anyerr then
       null;
end before each row;

after statement is
begin
  null;
   EXCEPTION
     when others then
      null;
end after statement;
  
end;

any suggestions?

regards Wilko