It is something to do with FSUIPC.
See this thread:
http://milviz.com/forum/viewtopic.php?f=220&t=11080
I know it's not Ezdok but here is the important part.
"You can use FSUIPC, your axis profile for the T-38 must just look like this:
[Axes.Jet_2_Stick_T-38]
RangeRepeatRate=10
0=3X,256,F,66388,0,0,0 -{ TO SIM: AXIS_RIGHT_BRAKE_SET }-
1=3Y,256,F,66387,0,0,0 -{ TO SIM: AXIS_LEFT_BRAKE_SET }-
2=3Z,256,F,65764,0,0,0 -{ TO SIM: AXIS_RUDDER_SET }-
3=4Z,256,F,66423,0,0,0 -{ TO SIM: AXIS_THROTTLE2_SET }-
4=4R,256,F,66420,0,0,0 -{ TO SIM: AXIS_THROTTLE1_SET }-
5=5X,256,F,65763,0,0,0 -{ TO SIM: AXIS_AILERONS_SET }-
6=5Y,256,F,65762,0,0,0 -{ TO SIM: AXIS_ELEVATOR_SET }-
The important part is the TO SIM and AXIS events.
What's happening is your afterburner threshold has not be set. The MVAMS looks at your P3D controls config for your throttle assignments so it can read your throttle and set the afterburner threshold, but if those are missing as is the case with FSUIPC controls, you need to make sure your FSUIPC is configured properly, and then use the Set Afterburner Threshold from the Addons menu->Milviz T-38A."