Disable back button of fv11 tcode .

Hi,

I am using fv11 BDC to update the records . we have multiple key combinations for each condition type, so I am directly giving item screen to user through bdc recording to enter the values manually. In some cases user clicked on back button it is going to initial screen of fv11. here user can select any other key combination so we need to avoid that so is it possible to disable back button ???? bcz if user select cancel button it is leaving the program.

thanks,

Mohan.