Polish to URL encode


I’ve been pondering this problem for some time now, and I need someone to correct me if Im wrong. Im trying to make a little search box to input a Polish word, so that Flash will url encode it, add then add it to and address and display the result on a html page.
Now, the problem that I came upon is as far as Im know, that some of the Polish signs aren’t supported by the URL encoding. From what I’ve read from google, most of the Polish signs are ISO-8859-1 encoded, BUT there are a few like: “S” with an ’ on top of it, that is coded in ISO-LATIN-2 which isn’t in the URL encode list.

Could anyone verify this?