samba - Jun 2013 - how to delete a locked file in smbclient.

I have a samba server in linux and two samba client in windows.

in window xp, I use jcifs to access the file in samba server.
sometimes, a client will lock a file and the other client can't want to
delete the file.
but the client will delete the locked file unsuccesssfully, this is not my
expectation.

so i want to know, is there any configuration in smb.conf to allow clients
delete a locked file.

or in jcifs, can I delete a locked file by force

Thanks for any reply.