Why my approach to create a codecave is not working ?

[Healian]

Well i am trying to create a codecave... this is my first time trying. i have injected the dll successfully in the target but my custom codecave is not getting called

#include <Windows.h>

__declspec(naked) void codecave()
{
	__asm
	{
		PUSHAD
		PUSHFD
	}

	MessageBox(NULL, "ROCK", "THE", MB_ICONINFORMATION);

	__asm
	{
		POPFD
		POPAD
		ret
	}
}

__declspec(naked) void *shortcut(const byte *dst)
{
	__asm{
		jmp dst
	}
}

void CreatRoute(byte *src, const byte *dst)
{
	DWORD oldProtection;
	VirtualProtect(src, sizeof(dst), PAGE_EXECUTE_READWRITE, &oldProtection);
	memcpy((byte*)shortcut(dst), src, sizeof(dst));
	VirtualProtect(src, sizeof(dst), oldProtection, &oldProtection);
}

BOOL WINAPI DllMain(HMODULE hModule, DWORD dwReason, LPVOID lpReserved)
{
	switch (dwReason)
	{
	case DLL_PROCESS_ATTACH:
		MessageBox(NULL, "DLL loaded!", "MyDLL", MB_ICONINFORMATION);
		CreatRoute((BYTE*)0x00E54D20, (BYTE*)codecave);
		break;
	case DLL_PROCESS_DETACH:
		MessageBox(NULL, "DLL unloaded!", "MyDLL", MB_ICONINFORMATION);
		break;
	default:
		break;
	}

	return TRUE;
}