To have the L-1011 start in a cold n dark setting, you need to start FSX with a default aircraft, like the C172, and get it to a cold n dark setting, then load the L-1011.
Alternatively. You can set a the default flight to a cold n dark setting. My default flight in FSX is the C172 in a cold n dark setting, except that the Avionics Switch is ON, so every time I load the L-1011 into FSX, it's in a cold n dark setting (except for the Avionics). I have set it this way specifically for Captain Sim products because they don't have an Avionics Switch (except the CS737), and I don't have to use the keyboard shortcut to get the avionics working.
The L-1011 Cleared for Takeoff (KSEA) should be exactly that, ready for takeoff with the engines running, flaps set, etc. You can load this flight at any time by either loading at the FSX start screen (and selecting Fly Now), or loading it via the menu in FSX (Menu > Flights > Load > select flight > Fly Now!). There should also be a flight named L-1011 Cold-n-Dark (KSEA).

Starting the engines on  the L-1011 require a precise method.
Second Officer's Lower Panel
1. You need the APU running, with Bleed Air S/O switch ON (APU Control)
Second Officer's Upper Panel
2. Set both ATM Mode Selector switches to OFF (Hydraulics)
3. Engine 1, 2, and 3 Pack Flow Control Switches OFF (Engine Bleed Control)
Overhead Panel
4. You can now start the engines using the Ground Start Switches (Engine Start)

You can also view the engine start video by Captain Sim here: https://www.youtube.com/watch?v=zDFCvy9jyr8