WPF WebBrowser: changing pront dialog properties programmatically

I'm writing application with WPF WebBrowser control. It's source is result of xml/xslt sourse from database.

In the window that contains WebBrowser there is button for printing with handler:

mshtml.IHTMLDocument2 doc = WBrowser.Document as mshtml.IHTMLDocument2;
doc.execCommand("Print", true, 0);

but in this case there is no background in printed document. I've researched this issue, and it's trouble with property in Internet Explorer page setup dialog - Allow the printing of background colors and images.

I've tried to change this by this code:

RegistryKey regKey = Registry.CurrentUser
        .OpenSubKey("Software", true)
        .OpenSubKey("Microsoft", true)
        .OpenSubKey("Internet Explorer", true)
        .OpenSubKey("PageSetup", true);

var defaultValue = regKey.GetValue("Print_Background");
regKey.SetValue("Print_Background", "yes");

but this is bad code. I don't want to change registry values for one simple bool parameter.

So, my question is: how can I change this parameter programmatically without registry modification?

Thank you!