[Bioperl-l] How to change gap open penalty

[Julio Fernández Banet]

Hello.
i would like to know if it is posible to change the gap open penalty 
value of bl2seq.
My code looks like this:
   # Run bl2seq with the two sequences
     $factory=Bio::Tools::Run::StandAloneBlast->new('program'=>'blastn', 
'G'=>'0' ,'outfile'=>"$Seq.out");
     my $bl2seq_report=$factory->bl2seq($Seq1, $Seq2);

But it seems that it doesn't not work. any suggestion????
Thanks