Hi Kaushik,
For 1:
Please check the following and the related TecNet sites that describe how credit Card payments can be made.
technet.microsoft.com/.../gg232216.aspx
Please also Google for the respective Whitepaper "Changes to credit card processing in Microsoft Dynamics AX..."
For 2:
Why do you need an authorization for the second payment option? Isn't this a process where the customer simply makes e.g. an electronic payment that you need to settle? Is process no. 2 also related to credit Card payments?
Best regards,
Ludwig