Windows XP how to invoke Ras Custom -scripting Dll?

[smallcat0008]

I do everything that the MSDN tell.
1.the RASEO_CustomScript option in the phone-book entry for the connection
2.RDEOPT_UseCustomScripting flag in the RASDIALEXTENSIONS structure
3.create a value with the name CustomScriptDllPath
HKEY_LOCAL_MACHINE
System
CurrentControlSet
Services
Rasman
Parameters

but when dial out,the application can't invoke the RASCS_Interactive state,why?who can tell me? (I develop the application on windows XP,I doubt whether the Ras Custom -scripting Dll can developed on windows xp)