How to start the APU via "THIRD_PARTY_EVENT"

Guten Tag aus Berlin.

Aircraft: PMDG 737NGX P3D V1.10.6461

FlightSim: P3D V3 3.0.10.14945

Today I received my new HOTAS WARTHOG.

I'd like to assign switches to "special" PMDG 737 functions.

Using FSUIPC V4.948 I've been able to find some general functions.

Using the CDU(FMC) -> PMDG SETUP -> OPTIONS -> KEY COMMANDS -> ... I've found some further options to assign PMDG functions to swithes using Key-Commands.

I was searching for an option "Taxi Light" to learn, there is nothing assigned.

So I've "googled" and found informations about the file ..(FSIM)\PMDG\PMDG 737 NGX\SDK\PMDG_NGX_SDK.h

In line #519 the THIRD_PARTY_EVENT_ID_MIN number is defined by 69632

Beginning at lIne #583 the "define EVT" section show various PMDG options.

I've learned, I could use them with FSUIPC -> Buttons + Switching -> Select for FS Control -> <custom control>

and if I'd like to switch on the Taxi-Light I need to type in 69749, which is 69632 plus 117,

because of (EVT_OH_LIGHTS_TAXI (THIRD_PARTY_EVENT_ID_MIN + 117)

Using the Parameter 1 (on) and 0 (off) I can switch the taxy lights on and off.

I thought, I could start the APU the same way, but unfortunately when I use the ID 69750, which is marked as "APU Start" in the file (+118), I'm able to switch the APU on and off only, but not to start (ignite).

This is, what I know... Does someone know more ? How can I start the APU using a USB-Controller switch...

Danke!

Ralf Fitzner