Add the 2 lines in bold.

Code:
selected diplomat
{
	over own
	{
		land						Mov Mov
		sea							Na Na				tooltip characters_cannot_go_on_sea
		army						Mer* (S) Mer (S)
		admiral						Em*  (S) Em  (S)	tooltip embark_character
		diplomat					S  (S) S (S)
		spy							S  (S) S (S)
		assassin					S  (S) S (S)
		family						S  (S) S (S)
		settlement					G* (S) G  (S)		tooltip enter_settlement
		fort						G* (S) G  (S)		tooltip enter_fort
		rally_point					Mov
		naval_rally_point			Na Na				tooltip characters_cannot_go_on_sea
		garrisoned_settlement		G*  (S) G  (S)		tooltip enter_settlement
		garrisoned_fort				G*  (S) G  (S)		tooltip enter_fort
		garrisoned_ship				Em* (S) Em (S)		tooltip embark_character
		sieged_settlement			S					tooltip cannot_enter_sieged_settlement
		sieged_fort					S					tooltip cannot_enter_sieged_fort
		garrisoned_dock				Mer* (S) Mer (S)
		port						Mov
		dock						Na	
	}
	over enemy
	{
		default						Na					tooltip cannot_perform_mission

		land						Mov Mov
		sea							Na Na				tooltip characters_cannot_go_on_sea
		army						TB	Na				tooltip diplomacy_mission
		diplomat					T	Na				tooltip diplomacy_mission
		assassin					TB
		family						T	Na				tooltip diplomacy_mission	
		settlement					T	Na				tooltip diplomacy_mission
		fort						T	Na				tooltip diplomacy_mission
		rally_point					Mov
		naval_rally_point			Na Na				tooltip characters_cannot_go_on_sea
		garrisoned_settlement		TB	Na				tooltip diplomacy_mission
		garrisoned_fort				TB	Na				tooltip diplomacy_mission
	}
	over allied
	{
		default						Na					tooltip cannot_perform_mission

		land						Mov Mov
		sea							Na Na				tooltip characters_cannot_go_on_sea
		army						TB	Na				tooltip diplomacy_mission
		diplomat					T	Na				tooltip diplomacy_mission
		assassin					TB
		family						T	Na				tooltip diplomacy_mission	
		settlement					T	Na				tooltip diplomacy_mission
		fort						T	Na				tooltip diplomacy_mission
		rally_point					Mov
		naval_rally_point			Na Na				tooltip characters_cannot_go_on_sea
		garrisoned_settlement		TB	Na				tooltip diplomacy_mission
		garrisoned_fort				TB	Na				tooltip diplomacy_mission
	}
}