@@ -1430,10 +1430,23 @@
 {
 	OFMutableString *new = [[string mutableCopy] autorelease];
 
 	[new appendString: self];
 
+	[new makeImmutable];
+
+	return new;
+}
+
+- (OFString*)stringByReplacingOccurrencesOfString: (OFString*)string
+				       withString: (OFString*)replacement
+{
+	OFMutableString *new = [[self mutableCopy] autorelease];
+
+	[new replaceOccurrencesOfString: string
+			     withString: replacement];
+
 	[new makeImmutable];
 
 	return new;
 }