even though the HU doesnt have the facility of "safely remove hardware" you can switch off the HU completely before pulling off the pen drive.
secondly you can do one thing. connect the pen drive to PC. on the drive click properties. one dialog box will open named removable disc properties. click on your pen drive from the list and click on properties. go to policies TAB and select " Optimize for Quick Removal " . your pen drive will be ready for removal without clicking safely remove hardware.
