How to set page layout programmatically

 Hi,

I want to change page layout "a5" size and "landscape" orientation (with c#). I try this:

options.AdditionalGhostscriptParameters = "-sPAPERSIZE=a5 -dORIENT1=false";

and this:

options.Papersize = "a5";

But it didn't. How can I do this.

Thanks.