Hi Santhosh,
Let's assume that you have done all the requirements in front end and back end system,
the most common issue are most likely came from the business process itself (in your back end system).
Have you assign the Sales Employee (the same ID with the ID used for your rfc connection) to your specific customer?
In my opinion, you cant see any customer since you haven't assign your ID you are currently using to any customer yet.
The tcode you'll need are PA30, and XD02 in your back-end system.
If you have trouble with this configuration please ask for help from your SD consultant.
Hope it helps 
BR,
Jean Rijkaard