HI Vamsi,
In Define Transaction Types., you can check the option Permit Premium/Discount. This will open a new field in transaction structure where you can input the Nominal amount and payment amount. The difference between the 2 will be amortized.
You would also need to assign a Amortization step in your PMP with appropriate amortization method.
For details on the calculation of various available Amortization methods please refer notes - 864857 and 1117778. EIR and IRR will also be determined.
Regards,
Nikhil