how to configure our company logo in SA server login page
As far as I know, that's not possible.
You can configure the Login Banner (text) under Admin->Security-> Login Banner.
You can configure your company logo for reports Admin->Services-> Select Reporting engine-> Config-> Manage Logos Tab.
I hope this helps.
It looks like RSA PS may have modified the root.war file that makes up the interface.
Basically this is a Zip file that can be extracted and then repacked.
When the jetty service starts it creates a temp directory and extracts the contents of the .war file.
This is extracted to : /tmp/jetty-0.0.0.0-443-root.war-_-any-/webapp/resources/images/common
The image picture is rsa-sa-logo.png
You could replace this file with your own one. A better idea would be to have a cron job which copies your own image over this file in the temp directory on a regular basis.
However please note that this would not be supported by RSA Support and if you break your system you would be on your own.