I tried to reproduce your problem, but so far I can't. Please tell me
1. What version of LV are you using?
2. What version of .NET are you using?
3. What language are you running? Do you know which codepage your system is set to?
4. Can you post a simple, complete example? A simple .NET dll that just takes a string and returns it, and a string control with the default value set to the problem string?
I did #4 myself, and copied the string off the webpage, but the actual character value might have changed going from your system, to HTML, to my system, so putting it into the VI is the best option.