Silverlight 5 force vector printing isn't working

I'm printing these telerik reports.  I guess that doesn't matter, but I'm creating a Print Document from it.

Now, when I use a normal desktop and print, everything works fine, it's in vector and the size is 1 MB for the printer spool.

Now when I use this silverlight 5 program oob on a VDI (Virtual desktop instance, my customers are using this), it seems to print in Bitmap, because the size is 100MB now in the spool (same printer).  I did the following code to force vector printing, but no luck.  Maybe this is a VDI issue?  I don't know much about this area

            PrinterFallbackSettings settings = new PrinterFallbackSettings();
            settings.ForceVector = true;
            settings.OpacityThreshold = 0.5;

            this.printDocument.Print("document", settings,true);

dan