Cannot print other formats than A4

I have a serious problem with not being able to print documents in A3. Printing in A3 from Mac applications works fine, all the settings within Windows match a comparable native Win7 machine, but still printing A3 from within parallels will only produce an A4 print (on A3 paper).

No combination of selecting a printer in the parallels settings and/or within Windows has brought any improvement.

I urgently need to fix this and appreciate any helpful hints.