HTTP with SSL certificates using BizTalk

HTTP posting from a BT HTTP send port may fail due to 3 reasons: Wrong config at HTTP port, Wrong certificate location or Wrong certificate installation.
To Receive http post (decryypt) with SSL you need to have you own private certificate installed in your Local Machine Personal folder under Certificate snap-in in MMC. To Send http post (encrypt) with SSL, you need to have the trading partner public certificate installed in the Other People folder in MMC-Certificate store.

Note: You need to log in to the server using the BizTalk Service Acc (the acc under which BT runs) to install the certificate both own private certificates (into Personal folder) or trading partner public certificates(into Other People folder.... if not in Personal folder)

All the information is available on MSDN, here is the coolest link.
http://msdn2.microsoft.com/en-us/library/aa953654.aspx

How to install Trading partner Public Certificates in server:
Open the trading partner URL (eg. https://xyz.abcd.com/pqr/lkj.aspx) in IE and it may ask for userid and password. Once the page opens go to File menu -> Properties ->Click Certificate Button ->Click Install Certificate button. (You can get the Thubmprint of the certificate there at the Detail tab) It will open the cert installation wizard. Used default settings and istall it. You can also change the folder location of the certificate to istall in a diff folder.
The thumbnail needs to be put in the HTTP send port configuration while configuring the BT HTTP send port.

How to install Own Private Certificate:
Get the certificate file copied to you local hard disk. Opwn MMC-Certificate snap-in, the right click on Personal folder and Import the certificate.