diff --git a/sylk/configuration/settings.py b/sylk/configuration/settings.py
index 7e4396c..4588905 100644
--- a/sylk/configuration/settings.py
+++ b/sylk/configuration/settings.py
@@ -1,121 +1,121 @@
 # Copyright (C) 2010-2011 AG Projects. See LICENSE for details.
 #
 
 """
 SIP SIMPLE SDK settings extensions.
 """
 
 __all__ = ['AccountExtension', 'BonjourAccountExtension', 'SylkServerSettingsExtension']
 
 import os
 
 from sipsimple.account import MSRPSettings as AccountMSRPSettings, NATTraversalSettings as AccountNATTraversalSettings
 from sipsimple.account import RTPSettings as AccountRTPSettings, SIPSettings as AccountSIPSettings, TLSSettings as AccountTLSSettings
 from sipsimple.configuration import CorrelatedSetting, Setting, SettingsObjectExtension
-from sipsimple.configuration.datatypes import AudioCodecList, MSRPTransport, NonNegativeInteger, Path, Port, PortRange, SampleRate, SIPTransportList, SRTPEncryption
+from sipsimple.configuration.datatypes import MSRPTransport, NonNegativeInteger, Path, PortRange, SampleRate, SIPTransportList, SRTPEncryption
 from sipsimple.configuration.settings import AudioSettings, LogsSettings, RTPSettings, SIPSettings, TLSSettings
 
 from sylk import __version__ as server_version
 from sylk.configuration import ServerConfig, SIPConfig, MSRPConfig, RTPConfig
-from sylk.configuration.datatypes import SIPProxyAddress
+from sylk.configuration.datatypes import AudioCodecs, Port, SIPProxyAddress
 
 
 # Account settings extensions
 
 msrp_transport = 'tls' if MSRPConfig.use_tls else 'tcp'
 class AccountMSRPSettingsExtension(AccountMSRPSettings):
     transport = Setting(type=MSRPTransport, default=msrp_transport)
 
 class AccountNATTraversalSettingsExtension(AccountNATTraversalSettings):
     use_msrp_relay_for_inbound = Setting(type=bool, default=False)
     use_msrp_relay_for_outbound = Setting(type=bool, default=False)
 
 class AccountRTPSettingsExtension(AccountRTPSettings):
-    audio_codec_list = Setting(type=AudioCodecList, default=RTPConfig.audio_codecs, nillable=True)
+    audio_codec_list = Setting(type=AudioCodecs, default=RTPConfig.audio_codecs, nillable=True)
     srtp_encryption = Setting(type=SRTPEncryption, default=RTPConfig.srtp_encryption)
     use_srtp_without_tls = Setting(type=bool, default=True)
 
 class AccountSIPSettingsExtension(AccountSIPSettings):
     register = Setting(type=bool, default=False)
     outbound_proxy = Setting(type=SIPProxyAddress, default=SIPConfig.outbound_proxy, nillable=True)
 
 tls_certificate = Path(ServerConfig.certificate) if ServerConfig.certificate and os.path.isfile(ServerConfig.certificate) else None
 class AccountTLSSettingsExtension(AccountTLSSettings):
     certificate = Setting(type=Path, default=tls_certificate, nillable=True)
     verify_server = Setting(type=bool, default=ServerConfig.verify_server)
 
 class AccountExtension(SettingsObjectExtension):
     enabled = Setting(type=bool, default=True)
 
     msrp = AccountMSRPSettingsExtension
     nat_traversal = AccountNATTraversalSettingsExtension
     rtp = AccountRTPSettingsExtension
     sip = AccountSIPSettingsExtension
     tls = AccountTLSSettingsExtension
 
 
 class BonjourAccountExtension(SettingsObjectExtension):
     enabled = Setting(type=bool, default=False)
 
 
 
 # General settings extensions
 
 class AudioSettingsExtension(AudioSettings):
     input_device = Setting(type=str, default=None, nillable=True)
     output_device = Setting(type=str, default=None, nillable=True)
     sample_rate = Setting(type=SampleRate, default=16000)
 
 
 log_directory = Path(ServerConfig.trace_dir) if ServerConfig.trace_dir else None
 class LogsSettingsExtension(LogsSettings):
     directory = Setting(type=Path, default=log_directory)
     trace_sip = Setting(type=bool, default=ServerConfig.trace_sip)
     trace_msrp = Setting(type=bool, default=ServerConfig.trace_msrp)
     trace_pjsip = Setting(type=bool, default=False)
     trace_notifications = Setting(type=bool, default=ServerConfig.trace_notifications)
 
 
 class RTPSettingsExtension(RTPSettings):
     port_range = Setting(type=PortRange, default=PortRange(RTPConfig.port_range.start, RTPConfig.port_range.end))
     timeout = Setting(type=NonNegativeInteger, default=RTPConfig.timeout)
 
 
 def sip_port_validator(port, sibling_port):                                                                                                                                                  
     if port == sibling_port != 0:
         raise ValueError("the TCP and TLS ports must be different")
 
 transport_list = []
 if SIPConfig.local_udp_port:
     transport_list.append('udp')
 if SIPConfig.local_tcp_port:
     transport_list.append('tcp')
 if SIPConfig.local_tls_port:
     transport_list.append('tls')
 
 udp_port = SIPConfig.local_udp_port or 0
 tcp_port = SIPConfig.local_tcp_port or 0
 tls_port = SIPConfig.local_tls_port or 0
 
 class SIPSettingsExtension(SIPSettings):
     udp_port = Setting(type=Port, default=udp_port)
     tcp_port = CorrelatedSetting(type=Port, sibling='tls_port', validator=sip_port_validator, default=tcp_port)
     tls_port = CorrelatedSetting(type=Port, sibling='tcp_port', validator=sip_port_validator, default=tls_port)
     transport_list = Setting(type=SIPTransportList, default=transport_list)
 
 
 ca_list = Path(ServerConfig.ca_file) if ServerConfig.ca_file and os.path.isfile(ServerConfig.ca_file) else None
 class TLSSettingsExtension(TLSSettings):
     ca_list = Setting(type=Path, default=ca_list, nillable=True)
 
 
 class SylkServerSettingsExtension(SettingsObjectExtension):
     user_agent = Setting(type=str, default='SylkServer-%s' % server_version)
 
     audio = AudioSettingsExtension
     logs = LogsSettingsExtension
     rtp = RTPSettingsExtension
     sip = SIPSettingsExtension
     tls = TLSSettingsExtension