Office Web App with Lync 2013 New-OfficeWebAppsFarm issue

Hi all!

I've read another posts in technet forums and google, but none helped me... Im installing office web app 2013 in windows 2008 r2 sp1 to use with lync 2013... my lync 2013 works fine (except office web apps resources, of course) and after install all pre-requisites (modules and patches), the office web app itself, i get a error when i run powershell command (both elevated mode or not):

New-OfficeWebAppsFarm -InternalUrl "https://owa.local.domain" –CertificateName "xxxx" (where xxxx is my cert friendly name, as shown in IIS).

The error message is:

New-OfficeWebAppsFarm : The Office Web Apps service failed to start. See the Windows Application Event Log for more
details.
At line:1 char:1
+ New-OfficeWebAppsFarm -InternalUrl https://owa.local.domain–CertificateName ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OperationStopped: (:) [New-OfficeWebAppsFarm], ApplicationFailedException
    + FullyQualifiedErrorId : AgentManagerStartFailed,Microsoft.Office.Web.Apps.Administration.NewFarmCommand

At event viewer:

Service cannot be started. System.Runtime.InteropServices.COMException (0x80070520): A specified logon session does not exist. It may already have been terminated. (Exception from HRESULT: 0x80070520)
   at Microsoft.Web.Administration.Interop.IAppHostMethodInstance.Execute()
   at Microsoft.Web.Administration.BindingManager.Save()
   at Microsoft.Web.Administration.ServerManager.CommitChanges()
   at Microsoft.Office.Web.Environment.WacServer.AgentManager.AgentController.ProvisionTopLevelSites(IEnumerable`1 webAgentsToRun)
   at Microsoft.Office.Web.Environment.WacServer.AgentManager.AgentController.StartAgents()
   at Microsoft.Office.Web.Environment.WacServer.AgentManager.AgentManagerApplication.OnStart(String[] args)
   at System.ServiceProcess.ServiceBase.ServiceQueuedMainCallback(Object state)

So, any clue?

Thanks!