Use of existing signed certificate in Cognos V11

[RiRo]

Hi!

I have installed Cognos V11 on a Linux machine.
There is an other app inclusive a webserver installed and they have created a CSR with openssl and sent this CSR to the external CA for signing. After that, they have importet the signed certificate in their app/webserver.

My question is, can I took this existing signed certificate and use it to encrypt my Cognos BI User Interface with SSL?
Or is there the need to create an own CSR with Cognos tools?

If that should work, with which tool should I work to import that existing certificate, because there are some tools for certs available?
Do I have to import the key too?

Thanks
Robert