To get the 6 PWM levels required for six flight modes with a JETI radio DC-16 or DS-16, the procedure is very simple (I have the JETI firmware in French, so I'm not sure of the expressions used for the menus in English):
1) In the menu FUNCTION DEFINITION create a function "Pilot" and assign to it the switch "Se" for example, and create another function "Pilot2" and assign to it the switch "Sf".
2) In SERVO ASSIGNMENT assign Pilot function to channel 8. The Pilot function has to be "Global", and its function curve "standard".
2) In FREE MIX create a mixer from Pilot2 to Pilot with Master value = 25%
3) In SERVO SETTINGS go to the Pilot channel (8). Adjust the Neutral to -134 and the Positive Max to 104. The value of Max Negative remains to -100.
Well, that's all. In RECEIVER OUTPUT you can verify that the different positions of the swiches give the following percentages:
63 which corresponds to the PWM level 1815