Hi , Finally figured out a way to customize HANA default log-in form .Below is the step by step approach:-
1.Open web IDE .There you will see a package called sap.
2.Navigate to sap/hana/xs/formLogin
3.Open the ui folder .Navigate to ui/login.There you will see App.view.js.
Here is where all the codes regarding the login page is written . Lets start with some changes
Here for the time being i have de-referenced the text from the i18n file .This will appear in the login form as
I have also changed the log-on button type.
Here Change the header text,logo,footer text
Also you can change the background image from DIY SAP HANA login screen background in 3 steps
Finally your login page will look like