Well, you need to add a record to "Obstacles.simba".
Example:
OBS_LADDER_MG_DOWN:
with result do
begin
Name := 'OBS_LADDER_MG_DOWN';
ObjConst := LADDER_MG_DOWN;
ObjMir := LADDER_MG_UP;
ObjMirArea := intToBox(MSCX - 85, MSCY - 85, MSCX + 85, MSCY + 85);
Camera := ['n', true];
// West, South, East, North
EndTiles := [Point(3017, 9739), Point(3019, 9737),
Point(3021, 9739), Point(3019, 9741)];
end;
OBS_LADDER_MG_UP:
with result do
begin
Name := 'OBS_LADDER_MG_UP';
ObjConst := LADDER_MG_UP;
ObjMir := LADDER_MG_DOWN;
ObjMirArea := intToBox(MSCX - 85, MSCY - 85, MSCX + 85, MSCY + 85);
Camera := ['n', true];
// West, South, East, North
EndTiles := [Point(3017, 3339), Point(3019, 3337),
Point(3021, 3339), Point(3019, 3341)];
end;
Just make one for the altar, and one for the portal (If there is a portal on the other side?)