SSL Inspection not using Self Signed Certificate

Hi,

Is there a way to use SSL inspection using Internal Certificate Authority certs? It seems that SSL inspection only uses local certificate but the format ussualy is in PCKS#12 or the one with password and private key. I cannot seem to generate a CSR file that allows to generate a password or private key from within Fortigate. Installing certs on PC's is not applicable for our company as we have alot of PC's here. I was able to use our internal CA cert to get a secured fortigate management screen but can't seem to use the SSL inspection.

Appreciate your help.

Regards,

Ron