I would use the utaskerSerialBoot project but with usb_application.c (USB task) from utaskerV.4 project instead of usb_loader.c (original USB task in the loader project).

Probably it is easiest to configure the utaskerV1.4 project (you can open both projects in two simulators) for USB-MSD with SD card as reference and then you will know any additional defines necessary for it to be correct in the loader project.