Untested, but this is the general idea:
public boolean setEqualsIgnoreCase(Set a, Setb)
{
if (a.size() != b.size()) return false;
Iterator ai = a.iterator();
Iterator bi = b.iterator();
while(ai.hasNext())
{
if (!ai.next().equalsIgnoreCase(bi.next())) return false;
}
return true;
}