in reply to Re^2: Sending attachments in emails using SMTP
in thread Sending attachments in emails using SMTP
You probably should appeal to your company in that case to make an exception, because there's not much use in anyone here reinventing the wheel for you.
MIME::Lite is a pure perl module, and doesn't really need to be installed, worst case scenario you could unpack the whole thing into the same directory as your cgi/script.
Does your company not allow any use of modules, even ones that you maintain?