Diagram Question - AX3500 - Page 60 of Manual - Internal Transistor???

Can someone explain to me what \"Internal Transistor\" is referring to in FIGURE 28 on page 60 of the AX3500 Users Manual? I am trying to take advantage of Channel 3 to turn on a headlight on my robot project and can\'t figure out what Internal Transistor is referring to. Please help.

Note: I basically want to turn on a automotive 12v driving light. Any assistance would be apreciated.

-Sean