Don't do it. Don't convert. Do a re-write. Sorry, but even though the code CAN be converted, it doesn't mean it should be converted.
Please, in the name of cleaner code everywhere, spend the resource time to have it written correctly. View this as an opportunity to clean up the code, and take advantage of everything .Net brings to the table....
And I really don't care if I get negative rep'd on this one. If I convince one company to rewrite instead of convert, it was worth it.