If you mean this question I stick by my previous answer also posted there:
Generate a lookup table for Silverlight:
There is insufficient information provided in Silverlight to get the full font names without some form of lookup table.
I also provided the WPF code to generate such a table, in that previous question. If you do create such a lookup table, for the most common fonts, then the problem is solved.
That creation task just needs to be run on a machine with lots of fonts (or at least the fonts relevant to your target audience).
Anyone out there (with lots of fonts installed) care to generate a C# compatible table, using my source, and post it for cut & paste? :)