Bad URL in BSP applications for login

I have some BSP applications using the following URL for login (standard SAP login page):

/sap/public/bsp/sap/system/login.htm?sap-url=<%=PATHTRANS%>&bspchangepasswordvisible=X&bspclient=001&bspdontshowhttpswarning=X

this URL for login works good with a WAS 6.20 but not with a WAS 6.40

Does anybody have an idea of why ? or if there is another login page to call in the WAS 6.40 to have the same functionality ?