You should know that if you're installing our bootloader to sdb1, you will also need to modify the bootloader installed to the MBR before you can boot off our bootloader.
This is typically done by adding an entry to that other bootloader to chain load into the bootsector you want to boot. Not sure if you've done that
To sum it up, if you choose to install our bootloader to a bootsector (sda1, sdb1, etc) and you reboot without modifying the MBR bootloader, you will never see our boot options.