You can basicly took any bribe for allied faction, in Liberty Navy thats a lot: all Liberty corporations, Police, BHG, etc, all that will improve rep to Allied factions.
Ask someone to transfer you an LN ID in conn. Mount it and undock, and you'll be full green with the LN. Then dock again, sell it and remount your previous ID.
It might make factions hostile to the LN also hostile to you, though.