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.
Now to change the footer SAP-image to your company logo and to change the header goto login.html
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