gwbackup32 batch file

Using Gwbackup32 to backup Post Office and it works, the one issue is
that it is done from a batch file and for some reason it leaves the
output on the screen whereas dbcopy runs from a batch and automatically
exits once it is finished. Any ideas as to how to adjust this?
Here is the line in the batch file.

wback32 /po-h:\gwpoa /backup-o:\grpwise\gwpoa /silent

Thanks

Kiet