Why do you say that? Or are you hoping? I am more than curious what you have found. Although the E39 LCM has some smart features shared with the E38 most of it has the identical wiring of the E34 and that was all dumb switches.
I have not examined yet the electrical wiring diagrams nor the LCM source code (not coding options) but you could conclude this easily in the following ways:
1. the control over the signal lights is done completely discrete (all by the LCM), this is true to all lights on the E39 actually.
2. you can change status of all lights using SW only (i am using BMW 140 but NCS would probably be better)
3. check timings and delay when operating the turn signal lever - there is no-correlation between the frequency of hitting the lever vs. the amount of signals it'll yield.
4. there is a correlation between every "valid" turn signal lever hit and the delay from a single-light flicker of the turn signal
5. same like 4, only for the hazard lights, where you do have the ability to control the type of flashing (duty cycle and frequency)
From the above i would look for the function that operates the turning signals and (hopefully) find that the flash# is a parameter.
Any ideas how to get the source code for the LCM? (LCM3 / 4)