Permutation function with set STL

[chaosgeneration]

Hello,

I'm working on a function that is supposed to impose brute force algorithm on a set of chars. Here is what I have so far

set<string> permutation(set<char>S)
{
	set<string> fun;
	string myString;
	do{
		for(set<char>::iterator it=S.begin(); it !=S.end(); ++it){
			myString += *it;
		}
		fun.insert(myString);
	}while(next_permutation(S.begin(), S.end()));
	return fun;
}

due to my lack of knowledge of sets & stl, I've run into some difficulties. I believe that everything works properly except the next_permutations function. Any pointers?