http://www.c51.de/c51.de/Dateien/uVision2DLLs.php?Spr=EN&UIN=

How to install the extension DLLs

The DLLs work only with µVision2 V2.30 or higher versions.
1. Copy the DLLs in the subdirectory \keil\c51\bin.
2. Open the file TOOLS.ini in subdirectory \keil and include the following part in the section [C51]:

 AGSI1=SCOPE.DLL ("Scope simulation")
 AGSI2=LCD.DLL ("LCD simulation")
 AGSI2=LED.DLL ("LED simulation")
 AGSI3=I2C.DLL ("I2C simulation")
 AGSI4=Statemachine.dll ("8051 statemachine")
 AGSI5=Signalgenerator.dll ("Signal generator")
 AGSI6=Timemeasure.dll ("Timemeasure")
 AGSI7=TCPIP.dll ("TCPIP connection") 

!!!!If µVision2 is open during the procedure you have to restart it.
How the extension DLLs work

After starting the simulation you will find the following new entries in the folder Peripherals:
Scope
LCD
LED
I2C-Simul
8051 statemachine
Signal generator