bsd printing UNIX

I have a customer in which we setup bsd ports to print to remote printers, however the printer is not accepting my command line headers, -o landscape or the length of the page how can i associate a print driver such as a HP5SI to this bsd port to get call out functions I have the hex codes for the printer but it ignores my headers how can I resolve this also this customer uses a program called MFG pro which I am having the same problem with but it is unix based I’m sure if I can fix it unix I can resolve it in this application