if you already have a printer connected to the mac you can always set everything as if you have to print but when you get to the autocad print page you just have to select the pdf case in the bottom left and then select: save as postscript.
If you don't have any connected printer or if the printer format is not good and you need something bigger you can always create a virtual printer.
However, it is always possible to deceive the system by setting a custom format on the real printer connected to the computer. to say I set a sheet a0 on an a4 printer.
However if you want to create a new virtual printer, go to the system preferences of os x, select printers and scanners.
in the left list of printers (if you don't have it will be empty) on the bottom left there are a "+" button and a "-" button. select the "+" button.
will appear a new panel with top left: "default", "fax" "ip", "windows" (perhaps windows there is only if you have installed software as desktop parallels).
select "ip". where there is written address write: localhost or if you prefer an ip address of something you don't have in the network (something like 192.168.1.10 to give an example. but better if you write localhost).
in protocol leaves: "line printer daemon – lpd".
leaves empty tail.
where there is name will still appear localhost (or the number you entered). better change the name in something like: virtual printer.
leaves empty position.
to use: you can leave generic postscript printer or select one from the list.
if you use one normally in the office such as a postscript plotter, choose the one so much to have the same settings that you normally use in print but still it is not necessary. Obviously if you need a big size better choose a plotter.
I left the printer by default.
add prizes. He'll tell you the printer's not here. And then it's okay.
at this point you have inserted in the system a printer (unexistent) that you can use for your purposes.
Now every time you want to print follow the normal printing procedure but when you arrive at the fatidic print do not crush it.
select the pdf button at the bottom left of the print page and select: save as post script.. .
if you don't print from layout always remember to set the editing page setup when you give the autocad print.
you can find some indication on the setting procedure here:
http://forums.autodesk.com/t5/autocad-for-mac/can-t-export-oversize-pdfs-help/m-p/2825605#m924I hope you can solve this.
However, be careful to always check that the print settings are the ones you want because you know that you often forget to set the various items like the sheet size and its orientation etc..