In old firmware files there were a biss.key file, I do not know if in the last ones are too. In any case, if you can obtain this biss.key file I give two options by saving this file in an usb in the receiver:
1. With the usb connected to the receiver do a telnet to the receiver:
after login, execute command
to see the path of the mounted usb in my case is /tmp/UD0
and the execute vi biss.key
then you can edit the file (see vi commands in google)
save the file and then import this file with the emu.
2. The second option is by editing the file in your pc with a notepad or any kind of program.
To do this, ftp to the receiver:
edit the file in your computer and save, then ftp again
then import the file with the emu.
in both options I have assumed that the usb is mounted in /tmp/UD0
I hope that it can help