Changing printer paper size on iPad

Apple chatline are telling me you can't change paper size when printing from iPad.

Is Apple really that stupid?

I have a Canon printer with photo paper in tray one and A4 in tray 2.

The trays are not interchangeable. Every time I try to print from iPad it automatically prints on 6 x 4 photo paper from tray 1.

Let's assume I want to print screen from a website using Safari - I click on the square box with "Up arrow" at the top right of the screen. Then click on "Print" logo which gives me "Printer Options" That is pre-set with "Paper 4 x 6 inches"

If I try to click on "Paper" there is no option to change to A4.

Same happens if I try to print an e mail - it comes out on 6 x 4.

Has anybody got a workaround?

Can anyone suggest a 3rd party printing App?

Thanks