Rajneesh,
Ok, so the procedure is essentially the same for any unmanaged device. Soft or Hard phone
Firstly, you will need to create a SIP line to accept registration requests on Port 5060.
Next, you will need to create unmanaged stations in IA, each with a unique SIP username.
Finally, you need to configure the device (in your case, the softphone) to register with the IC server, using the SIP username specified above.
Feel free to ask follow-up question(s) if you need further explanation of any of this :-)