diff --git a/paramiko/hostkeys.py b/paramiko/hostkeys.py
index c8450b9..3ad0fe5 100644
--- a/paramiko/hostkeys.py
+++ b/paramiko/hostkeys.py
@@ -81,8 +81,7 @@ class HostKeyEntry:
         if self.valid:
             return '%s %s %s\n' % (','.join(self.hostnames), self.key.get_name(),
                    self.key.get_base64())
-        else:
-            return None
+        return None
 
 
 class HostKeys (UserDict.DictMixin):
@@ -230,21 +229,30 @@ class HostKeys (UserDict.DictMixin):
             raise KeyError(key)
         return ret
     
-    def __setitem__(self, key, value):
+    def __setitem__(self, hostname, entry):
         # don't use this please.
-        self._keys[key] = value
+        for key_type in entry.keys():
+            found = False
+            for e in self._entries:
+                if (hostname in e.hostnames) and (e.key.get_name() == key_type):
+                    # replace
+                    e.key = entry[key_type]
+                    found = True
+            if not found:
+                self._entries.append(HostKeyEntry([hostname], entry[key_type]))
     
     def keys(self):
         ret = []
         for e in self._entries:
             for h in e.hostnames:
-                ret.append(h)
+                if h not in ret:
+                    ret.append(h)
         return ret
 
     def values(self):
         ret = []
-        for e in self._entries:
-            ret.append({e.key.get_name() : e.key})
+        for k in self.keys():
+            ret.append(self.lookup(k))
         return ret
 
     def hash_host(hostname, salt=None):
diff --git a/tests/test_hostkeys.py b/tests/test_hostkeys.py
index dc43e79..b7d9ae9 100644
--- a/tests/test_hostkeys.py
+++ b/tests/test_hostkeys.py
@@ -41,6 +41,16 @@ AAAAB3NzaC1yc2EAAAABIwAAAIEA8bP1ZA7DCZDB9J0s50l31MBGQ3GQ/Fc7SX6gkpXkwcZryoi4k\
 NFhHu5LvHcZPdxXV1D+uTMfGS1eyd2Yz/DoNWXNAl8TI0cAsW5ymME3bQ4J/k1IKxCtz/bAlAqFgK\
 oc+EolMziDYqWIATtW0rYTJvzGAzTmMj80/QpsFH+Pc2M="""
 
+keyblob_dss = """\
+AAAAB3NzaC1kc3MAAACBAOeBpgNnfRzr/twmAQRu2XwWAp3CFtrVnug6s6fgwj/oLjYbVtjAy6pl/\
+h0EKCWx2rf1IetyNsTxWrniA9I6HeDj65X1FyDkg6g8tvCnaNB8Xp/UUhuzHuGsMIipRxBxw9LF60\
+8EqZcj1E3ytktoW5B5OcjrkEoz3xG7C+rpIjYvAAAAFQDwz4UnmsGiSNu5iqjn3uTzwUpshwAAAIE\
+AkxfFeY8P2wZpDjX0MimZl5wkoFQDL25cPzGBuB4OnB8NoUk/yjAHIIpEShw8V+LzouMK5CTJQo5+\
+Ngw3qIch/WgRmMHy4kBq1SsXMjQCte1So6HBMvBPIW5SiMTmjCfZZiw4AYHK+B/JaOwaG9yRg2Ejg\
+4Ok10+XFDxlqZo8Y+wAAACARmR7CCPjodxASvRbIyzaVpZoJ/Z6x7dAumV+ysrV1BVYd0lYukmnjO\
+1kKBWApqpH1ve9XDQYN8zgxM4b16L21kpoWQnZtXrY3GZ4/it9kUgyB7+NwacIBlXa8cMDL7Q/69o\
+0d54U0X/NeX5QxuYR6OMJlrkQB7oiW/P/1mwjQgE="""
+
 
 class HostKeysTest (unittest.TestCase):
 
@@ -86,3 +96,18 @@ class HostKeysTest (unittest.TestCase):
             i += 1
         self.assertEquals(2, i)
         
+    def test_4_dict_set(self):
+        hostdict = paramiko.HostKeys('hostfile.temp')
+        key = paramiko.RSAKey(data=base64.decodestring(keyblob))
+        key_dss = paramiko.DSSKey(data=base64.decodestring(keyblob_dss))
+        hostdict['secure.example.com'] = {
+            'ssh-rsa': key,
+            'ssh-dss': key_dss
+        }
+        self.assertEquals(2, len(hostdict))
+        self.assertEquals(2, len(hostdict.values()[0]))
+        self.assertEquals(1, len(hostdict.values()[1]))
+        fp = hexlify(hostdict['secure.example.com']['ssh-rsa'].get_fingerprint()).upper()
+        self.assertEquals('7EC91BB336CB6D810B124B1353C32396', fp)
+        fp = hexlify(hostdict['secure.example.com']['ssh-dss'].get_fingerprint()).upper()
+        self.assertEquals('4478F0B9A23CC5182009FF755BC1D26C', fp)