two way SSL and Trusted Certificate Authorities

Just to be clear, we're talking about the CA certs. You'll never have a copy of the private key, just the public certificate. If you open that cert up with a text editor, you'll either see gobbledeegook - which would be the "DER" binary-encoded format, or PEM - which will start with "===== BEGIN CERTIFICATE =====" and contain several lines of ASCII characters. This is the format you need. Take this text, plus the PEM-formatted text of all of the other CAs, and put that into a single text file. Example:

===== BEGIN CERTIFICATE =====
dhduejdushsudhsksjsjssnsjdnd
JsjdjdnjssjshavggbajHaukagHa
...
===== END CERTIFICATE =====
===== BEGIN CERTIFICATE =====
dhduejdushsudhsksjsjssnsjdnd
JsjdjdnjssjshavggbajHaukagHa
...
===== END CERTIFICATE =====

This will be your CA bundle file.