DKIM and SPF Setup for my emailserver

I use interspire to send emails. Interspire and powermta is already setup. In my interspire I use a different domain for from and reply address. In the email source, I have some issues with DKIM. I get this message: dkim=neutral (bad format) header.i= I need someone who can fix this issue and then show me how to do it. Also I need someone to show me how to set PTR records for each IP in my server. You must be an expert at server admin and server management. I will be asking you questions before commencing work to see your capability. Should be easy if you know what you are doing.