Running batch file evry 10 hours or so

Hello,
I need help with this....its URGENT
I've a Server running Windows Server 2003 Enterprise Edition.

Files from a program(Medware by Sage) needs to be backed up.I know the format of the particular files(.tps) which are to be backed up.I created a batch file to copy '.tps' files from 'C:\Medware' onto external drive(E:\)

My problem is: I want to run this batch file every 10 hours or so,so i tried to setup a Schedule Task operation.
When i select the Repeat Task every 10 hours,the Scheduler asks me to select Duration.
Files to be copied are a max. 20MB,so it doesn't take more than 10-15 mins.
Scheduler WONT allow me to select the duration shorter than 10 hours.

The Scheduler forces me to enter duration>10 hours,which means that the files backup once/day instead of every 10 hours

Is there a way to bypass this Duration setting??