[KWo]

static cell AMX_NATIVE_CALL csdm_setstyle(AMX *amx, cell *params)
{
	int len;
	char *name = MF_GetAmxString(amx, params[1], 0, &len);

	if (strcmp(name, "none") == 0)
	{
		g_SpawnMethod = -1;
		return 1;
	}

	SpawnMethod *pSpawn = NULL;

	for (size_t i=0; i<g_SpawnMngr.Spawns(); i++)
	{
		pSpawn = g_SpawnMngr.GetSpawn(i);
		if (strcmpi(pSpawn->GetName(), name) == 0)
		{
			g_SpawnMethod = i;
			return 1;
		}
	}

	return 0;
}

The value the function returns is "1" for each defined spawn method, "0" - if the spawn method is not defined. It looks like with that function You can probably somehow modify the spawn method from external plugin (but it needs csdm.inc for compilation), but every map change the method will be changed back to that what You have defined in csdm.cfg.