Can't see Free/Busy between Federated sites

We've been trying to get exchange 2010 federation working for a few weeks now and have come up empty right now.  Both sides are are Exchange 2010 SP1 and both have a business federation trust (was issue at beginning with consumer trust).  We had it working from one company to the other right after the SP was installed; however, the other side was never able to get back to the other.  So we tore everything down on both sides and have recreated both the federated trust with Microsoft and the trust between the orginizations.  Now neither side is working.  We've deleted and recreated the trust several times on both side and give it plenty of time but nothing has resolved the issue as of yet.  On both sides we get an error like below that has each others domains in the error.  Does anyone have anything we can try to get this working?

Process 3688: ProxyWebRequest FederatedCrossForest from S-1-5-21-2000478354-1645522239-725345543-2758 to https://owa.remotedomain.com/ews/exchange.asmx/WSSecurity failed. Caller SIDs: WSSecurity. The exception returned is Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequestProcessingException: System.Web.Services.Protocols.SoapHeaderException: An error occurred when verifying security for the message.
  at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
  at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.Proxy.Service.EndGetUserAvailability(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.FreeBusyApplication.EndProxyWebRequest(ProxyWebRequest proxyWebRequest, QueryList queryList, Service service, IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequest.EndInvoke(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.AsyncWebRequest.EndInvokeWithErrorHandling(). The request information is ProxyWebRequest type = FederatedCrossForest, url = https://owa.remotedomain.com/ews/exchange.asmx/WSSecurity
Mailbox list = <>SMTP:user@remotedomain.com, Parameters: windowStart = 1/30/2011 12:00:00 AM, windowEnd = 3/13/2011 12:00:00 AM, MergedFBInterval = 30, RequestedView = MergedOnly
. ---> System.Web.Services.Protocols.SoapHeaderException: An error occurred when verifying security for the message.
  at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall)
  at System.Web.Services.Protocols.SoapHttpClientProtocol.EndInvoke(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.Proxy.Service.EndGetUserAvailability(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.FreeBusyApplication.EndProxyWebRequest(ProxyWebRequest proxyWebRequest, QueryList queryList, Service service, IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequest.EndInvoke(IAsyncResult asyncResult)
  at Microsoft.Exchange.InfoWorker.Common.Availability.AsyncWebRequest.EndInvokeWithErrorHandling()
  --- End of inner exception stack trace ---
. Name of the server where exception originated: Exchange1. Make sure that the Active Directory site/forest that contain the user's mailbox has at least one local Exchange 2010 server running the Availability service. Turn up logging for the Availability service and test basic network connectivity.