Print to pdf with coloured background

[martinjsharp]

I am experimenting with the use of themes, with and without tiles to produce a dark blue background in line with corporate colours.  This is fine and I can produce a jpg or copy to Clipbaord.  But I cannot find the setting to allow me to print to pdf with the colour background. It seems to only print or print to pdf with a white (I assume no colour) background.
Any pointers to the required settings please. 

[martinjsharp]

Sparx Systems have responded and state "This is the intended behaviour for PDF generation".

[Paolo F Cantoni]

Sparx Systems have responded and stated, "This is the intended behaviour for PDF generation".

And is documented as such...

Paolo