Saving properties of a QObject based class

I want to save the properties of an object to an XML document and restore the properties later on. In a class that is derived from QWidget I created member functions that read and write my own member variables to an QDomDocument.

However, I would also like to store all the remaining properties, like the widget font, the palette, the size etc. Are there some ready-made functions somewhere that take any QObject based class and dump it as XML?

Related to that, how does the Qt designer actually create its ui files?

Thanks for any pointers...