How do I call informix stored procedures from Perl? I use DBD::ODBC to connect to informix database, but I don't know how to call procedures. my code like this:

my $dbh=DBI->connect("dbi:".DBDRIVE.":".DBNAME,DBUSER,DBPASS,{RaiseError=>0,PrintError=>0,AutoCommit=>1}) ||die $DBI::errstr;
    $dbh->do("execute procedure sp_test('2010-05-01 00:00:00')") || warn "failed\n";
    $dbh->disconnect(); 

when I run it, it didn't get error. But I get nothing when I check the database. the store procedure works fine if I run it in database directly. Anyone can help me out?