Manual method
DSCreateKey testkey
DSSignFile testkey.biprivatekey FFE_Medi99.pbo
Using DSUtils
Open DSUtils
Click the N button to create a new key
Name the Authority testkey
Note the name of the folder in which it is created
Ensure the new key is selected by clicking the folder icon and selecting the folder containing the new key
Drag and drop the .pbo file into the list section of the window
Click Process Files, the following is displayed in the message window
Added: FFE_Medi99
Added: 1
Processing FFE_Medi99.pbo (2 MB)...
Failed to sign FFE_Medi99.pbo
Failed to sign 1 file
Error description: 8009000b: Key not valid for use in specified state.