I am currently having troubles figuring out how to handle a filepath to be (dynamicly) passed out to a HyperLink control's NavigateUrl property.

Let's say that I'm trying to refer to a file named jäynä.txt at the root of C:.
Passing "file:///C:/jäynä.txt" result to a link to file:///C:/jäynä.txt, as does HttpUtility.UrlPathEncode("file:///C:/jäynä.txt").

Replacing the äs with %E4, which gives the string "file:///C:/j%E4yn%E4.txt", does give a working link to file:///C:/jäynä.txt, but I have not been able to find a way to make the replacement without defining it myself. With Replace("ä", "%E4"), for example.

Is there a way to automaticly handle the filepath string so that the HyperLink would display it correctly, without manualy listing what characters to replace in the string?

Additional Note:
There may be a way to work around this by spesifying the character encoding in which the page is rendered, because debugging shows that the HyperLink at least saves the string "file:///C:/jäynä.txt" unchanged, but somehow mangles it around the time of rendering.
However, this seems only be the case in rendering of the NavigateUrl because other components as well as HyperLink's Text-property are all quite capable of rendering the character ä unchanged.