Custom Pagesize formats

Hello Guys,

Is it possible to create/use a custom page size.

I have a database that allows users to create divider indexes which will be printed on the dividertabs 297x223.

The printer that I use is driven by a Fiery controller (a Standard printer controller and driver which is commonly used in the graphical industries) which can handle A4+ and A3+ sizes.

How can I set my print pagesize to A4+ (228x305 9"x12")

I now have defined an A3 format, but when I print it using the Fiery driver
and choose A4+ size I still get an A3 format printjob.

With kind regards Rene.