diff --git a/LEGO1/lego/legoomni/src/entity/legoworld.cpp b/LEGO1/lego/legoomni/src/entity/legoworld.cpp
index 1ba828cb..fe4bbc63 100644
--- a/LEGO1/lego/legoomni/src/entity/legoworld.cpp
+++ b/LEGO1/lego/legoomni/src/entity/legoworld.cpp
@@ -1,6 +1,7 @@
 #include "legoworld.h"
 
 #include "anim/legoanim.h"
+#include "extensions/siloader.h"
 #include "legoanimationmanager.h"
 #include "legoanimpresenter.h"
 #include "legobuildingmanager.h"
@@ -32,6 +33,8 @@ DECOMP_SIZE_ASSERT(LegoEntityListCursor, 0x10)
 DECOMP_SIZE_ASSERT(LegoCacheSoundList, 0x18)
 DECOMP_SIZE_ASSERT(LegoCacheSoundListCursor, 0x10)
 
+using namespace Extensions;
+
 // FUNCTION: LEGO1 0x1001ca40
 LegoWorld::LegoWorld() : m_pathControllerList(TRUE)
 {
@@ -636,6 +639,12 @@ MxCore* LegoWorld::Find(const char* p_class, const char* p_name)
 // FUNCTION: BETA10 0x100db3de
 MxCore* LegoWorld::Find(const MxAtomId& p_atom, MxS32 p_entityId)
 {
+	auto result =
+		Extension<SiLoader>::Call(HandleFind, SiLoader::StreamObject{p_atom, p_entityId}, this).value_or(std::nullopt);
+	if (result) {
+		return result.value();
+	}
+
 	LegoEntityListCursor entityCursor(m_entityList);
 	LegoEntity* entity;
 
diff --git a/assets/main.cpp b/assets/main.cpp
index bbb033b6..ca80ca40 100644
--- a/assets/main.cpp
+++ b/assets/main.cpp
@@ -12,19 +12,17 @@ uint32_t bufferCount = 8;
 
 std::string out;
 std::ofstream depfile;
+si::MemoryBuffer mxHd;
 
 void CreateWidescreen()
 {
 	si::Interleaf si;
-	si.Read("widescreen/GaraDoor.si");
-
-	si::Object* garadoor = dynamic_cast<si::Object*>(si.GetChildAt(0));
-	const char append[] = "Replace:\\Lego\\Scripts\\Isle\\Isle;1160";
-	garadoor->extra_.append(append, sizeof(append));
+	mxHd.seek(0, si::MemoryBuffer::SeekStart);
+	si.Read(&mxHd);
 
 	si::Object GaraDoor_Background_Wide;
-	const char extra[] = "World:current, RemoveWith:\\Lego\\Scripts\\Isle\\Isle;1161";
-	GaraDoor_Background_Wide.id_ = 5001;
+	const char extra[] =
+		"World:current, StartWith:\\Lego\\Scripts\\Isle\\Isle;1160, RemoveWith:\\Lego\\Scripts\\Isle\\Isle;1161";
 	GaraDoor_Background_Wide.type_ = si::MxOb::Bitmap;
 	GaraDoor_Background_Wide.flags_ = MxDSAction::c_enabled | MxDSAction::c_bit4;
 	GaraDoor_Background_Wide.duration_ = -1;
@@ -33,12 +31,11 @@ void CreateWidescreen()
 	GaraDoor_Background_Wide.presenter_ = "MxStillPresenter";
 	GaraDoor_Background_Wide.name_ = "GaraDoor_Background_Wide";
 	GaraDoor_Background_Wide.filetype_ = si::MxOb::STL;
-	GaraDoor_Background_Wide.location_ = si::Vector3(-240.0, 0.0, -1.0);
-	GaraDoor_Background_Wide.direction_ = si::Vector3(0, 0, 0);
-	GaraDoor_Background_Wide.up_ = si::Vector3(0, 1.0, 0);
+	GaraDoor_Background_Wide.location_.x = -240.0;
+	GaraDoor_Background_Wide.location_.z = -1.0;
 	GaraDoor_Background_Wide.up_.y = 1.0;
 	GaraDoor_Background_Wide.ReplaceWithFile("widescreen/GaraDoor_Background_Wide.bmp");
-	garadoor->AppendChild(&GaraDoor_Background_Wide);
+	si.AppendChild(&GaraDoor_Background_Wide);
 
 	std::string file = out + "/widescreen.si";
 	depfile << file << ": " << (std::filesystem::current_path() / "widescreen/GaraDoor_Background_Wide.bmp").string()
@@ -52,6 +49,12 @@ int main(int argc, char* argv[])
 	out = argv[1];
 	depfile = std::ofstream(argv[2]);
 
+	mxHd.WriteU32(si::RIFF::MxHd);
+	mxHd.WriteU32(3 * sizeof(uint32_t));
+	mxHd.WriteU32(version);
+	mxHd.WriteU32(bufferSize);
+	mxHd.WriteU32(bufferCount);
+
 	CreateWidescreen();
 	return 0;
 }
diff --git a/extensions/include/extensions/siloader.h b/extensions/include/extensions/siloader.h
index e4ed4d1e..e8c3fa9d 100644
--- a/extensions/include/extensions/siloader.h
+++ b/extensions/include/extensions/siloader.h
@@ -16,6 +16,7 @@ class SiLoader {
 
 	static void Initialize();
 	static bool Load();
+	static std::optional<MxCore*> HandleFind(StreamObject p_object, LegoWorld* world);
 	static std::optional<MxResult> HandleStart(StreamObject p_object);
 	static std::optional<MxBool> HandleRemove(StreamObject p_object, LegoWorld* world);
 
@@ -29,19 +30,17 @@ class SiLoader {
 	static std::vector<std::pair<StreamObject, StreamObject>> replace;
 
 	static bool LoadFile(const char* p_file);
-	static void ParseDirectives(
-		const MxAtomId& p_atom,
-		si::Core* p_core,
-		const MxAtomId* p_parentReplacedAtom = nullptr
-	);
+	static void ParseDirectives(const MxAtomId& p_atom, si::Core* p_core, MxAtomId p_parentReplacedAtom = MxAtomId());
 };
 
 #ifdef EXTENSIONS
 constexpr auto Load = &SiLoader::Load;
+constexpr auto HandleFind = &SiLoader::HandleFind;
 constexpr auto HandleStart = &SiLoader::HandleStart;
 constexpr auto HandleRemove = &SiLoader::HandleRemove;
 #else
 constexpr decltype(&SiLoader::Load) Load = nullptr;
+constexpr decltype(&SiLoader::HandleFind) HandleFind = nullptr;
 constexpr decltype(&SiLoader::HandleStart) HandleStart = nullptr;
 constexpr decltype(&SiLoader::HandleRemove) HandleRemove = nullptr;
 #endif
diff --git a/extensions/src/siloader.cpp b/extensions/src/siloader.cpp
index 121f742c..42b79548 100644
--- a/extensions/src/siloader.cpp
+++ b/extensions/src/siloader.cpp
@@ -36,6 +36,17 @@ bool SiLoader::Load()
 	return true;
 }
 
+std::optional<MxCore*> SiLoader::HandleFind(StreamObject p_object, LegoWorld* world)
+{
+	for (const auto& key : replace) {
+		if (key.first == p_object) {
+			return world->Find(key.second.first, key.second.second);
+		}
+	}
+
+	return std::nullopt;
+}
+
 std::optional<MxResult> SiLoader::HandleStart(StreamObject p_object)
 {
 	for (const auto& key : startWith) {
@@ -101,7 +112,7 @@ bool SiLoader::LoadFile(const char* p_file)
 	return true;
 }
 
-void SiLoader::ParseDirectives(const MxAtomId& p_atom, si::Core* p_core, const MxAtomId* p_parentReplacedAtom)
+void SiLoader::ParseDirectives(const MxAtomId& p_atom, si::Core* p_core, MxAtomId p_parentReplacedAtom)
 {
 	for (si::Core* child : p_core->GetChildren()) {
 		if (si::Object* object = dynamic_cast<si::Object*>(child)) {
@@ -129,8 +140,11 @@ void SiLoader::ParseDirectives(const MxAtomId& p_atom, si::Core* p_core, const M
 					}
 				}
 
-				if (p_parentReplacedAtom) {
-					replace.emplace_back(StreamObject{*p_parentReplacedAtom, id}, StreamObject{p_atom, object->id_});
+				if (p_parentReplacedAtom.GetInternal()) {
+					replace.emplace_back(
+						StreamObject{p_parentReplacedAtom, object->id_},
+						StreamObject{p_atom, object->id_}
+					);
 				}
 				else {
 					if ((directive = SDL_strstr(extra.c_str(), "Replace:"))) {
@@ -139,7 +153,7 @@ void SiLoader::ParseDirectives(const MxAtomId& p_atom, si::Core* p_core, const M
 								StreamObject{MxAtomId{atom, e_lowerCase2}, id},
 								StreamObject{p_atom, object->id_}
 							);
-							p_parentReplacedAtom = &replace.back().first.first;
+							p_parentReplacedAtom = replace.back().first.first;
 						}
 					}
 				}