Yes. We already found this out, and I have this in the newest SDK (yet unreleased):
The official additions should read:
at the top of Outpost2DLL.h:
// Marker Types
#define marker_cir 0 // circular
#define marker_dna 1 // dna strand
#define marker_lab 2 // beaker
in the TethysGame class declaration of Outpost2DLL.h:
static int __fastcall PlaceMarker(class Unit &, int x, int y, int markerType);
markerType MUST be one of those #defines at the top. Any other value will cause the game to crash.
The Unit parameter is useless as far as I saw, it has absolutely no effect on the marker. (I don't even think it's used in the official DLLs)
The marker doesn't really have any ties to a unit at all, in the game.
Note this is a marker only and doesn't serve as a "transporter" by itself.