Activesync - Dataviz & P990 - Wifi Works, but 3G doesn't

Hi,
I'm running SBS2003 connected through a wifi ADSL router.  Ports 80 and 443 are forwarded. I have a dynamic DNS and no SSL cert.  

The SOnyEricsson P990 comes with dataviz's Exchange Activesync.  I have gotten it to sync beautifully over a wifi link to the router (using the dynamic dns address) - it gives the sertificate error but goes ahead.

On a 3G link - for sync-ing from outside the office - it will not work.  Doesn't get as far as asking for the certificate.  Here is the log file - any comments or suggetions would be most welcome.

______________________________________________________________

Preparing to sync
CanConnectToInternet() - Checking Connection.
IAP : Ad-Hoc Bluetooth PAN, Type : LANService, ID : 4
IAP : Vodacom Internet, Type : OutgoingGPRS, ID : 5
IAP : Vodacom MMS, Type : OutgoingGPRS, ID : 6
IAP : Wless, Type : LANService, ID : 7
IAP : DefaultWiFiAccount, Type : LANService, ID : 9
IAP : PC Gprs 4, Type : OutgoingGPRS, ID : 10
SNAP : Internet, ID : 1
SNAP : Vodacom Internet, ID : 2
DSymbianV2InternetConnectEngine::SetupConnectionPrefs() - SNAP ID : 2
DSymbianV2InternetConnectEngine::RunL()
mCurrStage=0x1
statusCode=0x0
DSymbianV2InternetConnectEngine::RunL() - Network Status :0x1
Start synchronization...
 2.010 (314)
23/02/2007  9:06:21 am
Preparing to sync
DActiveSyncDataManager::PrepareForCalendarSync()
DActiveSyncDataManager::PrepareForContactsSync()
DActiveSyncDataManager::PrepareForEMailSync()
DSymbianMessageManager::HandleSessionEventL() - EMsvServerReady
DActiveSyncEngine::RunTask() -  Ready for StartSync
Looking for changed meetings
Looking for changed contacts
Looking for changed messages
DSymbianMessageManager::GetInbox() - EntryID : 0x100209
EstablishInternetTimeoutInternalL() - Time Out Sec : 2100
IAP used : 0x7
Bearer ID : 4
LAN Bearer
IAP used : 0x9
Bearer ID : 4
LAN Bearer
IAP used : 0x5
Bearer ID : 3
MODEM Bearer
LastSocketActivityTimeout : 3600
LastSocketClosedTimeout : 2100
IAP used : 0x6
Bearer ID : 3
MODEM Bearer
LastSocketActivityTimeout : 3600
LastSocketClosedTimeout : 2100
DSymbianV2InternetConnectEngine::Connect()
DSymbianV2InternetConnectEngine::SetupConnectionPrefs() - SNAP ID : 2
Connecting to Internet...
IConn - KStartingSelection : 0x0
IConn - KFinishedSelection : 0x0
IConn - KStartingSelection : 0x0
IConn - KFinishedSelection : 0x0
IConn - KFinishedSelection : 0x0
InternetConnect_ProgressUpdate() Stage - 2501, Error - 0
IConn - KConnectionOpen : 0x0
IConn - KConnectionOpen : 0x0
DSymbianV2InternetConnectEngine::RunL()
mCurrStage=0x2
statusCode=0x0
DSymbianV2InternetConnectEngine::RunL() : KErrNone - Connection created succesfully.
DSymbianHTTPSession::InternetConnect_RecievedResponse() - Connected To Internet
DSymbianHTTPSession::MakeReady() - Removing Validation Filter
Checking for Updates...
DActiveSyncEngine::PrepareGetItemEstimateCommand() : 0x9
DActiveSyncEngine::PrepareActiveSyncCommand() : 0x9
DActiveSyncDataManager::CollectCommandData() - ActiveSync command : 0x9
Initiating Submission of the HTTP Transaction (Symbian)
URL (Built) : http://myurl.hopto.org/Microsoft-Server-ActiveSync?User=David&DeviceId=359593003906667&DeviceType=RoadSyncClient&Cmd=GetItemEstimate
DSymbianHTTPTransaction::SubmitSymbianTransaction() - SubmitL() successfull.
Gprs connection successful: 0x5
Connection established!
DSymbianHTTPTransaction::OverallDataSize() - Data Size: 0x147
IConn - KLinkLayerOpen : 0x0
MHFRunL() - STATUS: 0xFFFFFFFFFFFFEC00
DSymbianHTTPSession::MHFRunL() - ERROR
DSymbianHTTPTransaction::CloseSymbianTransaction() - Closing.
DSymbianHTTPSession::DisconnectFromInternet()
DSymbianV2InternetConnectEngine::CloseConnection()
MHFRunL() - DONE: 0xFFFFFFFFFFFFEC00
*** Failed to connect to the server!  Please make sure that the "Server Name" is correct and try again.

Last sync: *ERROR* See log.
0x7370C06 (httpErrServerConnectFailed)
***Sync failed!
23/02/2007  9:07:42 am
DStargateAppUi::ActiveSync_ReportError():0x7370C06
DSymbianHTTPSession::MHFRunL()

DSymbianV2InternetConnectEngine::RunL()
mCurrStage=0x2
statusCode=0x0
DSymbianV2InternetConnectEngine::RunL() : KErrNone - closing connection.
DSymbianV2InternetConnectEngine::CloseConnectionInternal() : Disconnecting from the internet.
Disconnect Finished!
DSymbianHTTPSession::DisconnectFromInternet()
DSymbianHTTPSession::DisconnectFromInternet()