Question on HTTPs - SSL encryption

Hi Experts,

I understand that SSL is used to encrypt communication over internet.

Also went through the below doc for setting up SSL

http://help.sap.com/saphelp_nwpi71/helpdata/EN/14/ef2940cbf2195de10000000a1550b0/frameset.htm

However I have the following conceptual questions -

When PI is the client and receiver system is HTTPS server -

1. Do we need to get the certificate from receiver and install it in the keystore in NWA Or do we need to create it in PI and then get it signed by CA

    and send to receiver

2. What about the public and private key. Should PI set up the public received by receiver somewhere in NWA