One Global Setting For Multiple eMail Accounts!?

[qlmpnr]

I'm a newbie to iOS, iPhones & iPads so I may be missing something obvious, but why on earth can't you set Signature, 'Always Bcc Myself', etc. for each account instead of the setting applying to all of my 4 email accounts?
If this has been posted elsewhere, I'd appreciate a link.
Thanks - I love my iP4!