Remote Powershell session not loading assemblies

Question

I have a powershell script file, that when executed via winrm, wont get executed correctly in some windows environment.

The below script executes fine in that machine.

$ssrsEndpoint = "http://192.168.10.1/ReportServer/ReportService2010.asmx?WSDL"
$ssrsProxy = New-WebServiceProxy -Uri $ssrsEndpoint -Credential (Get-Credential)
$ssrsProxy.CreateFolder("NewFolder", "/", $null)

but, if executed via powershell remoting, it fails. ("localhost" is coming from a variable, so i don't have control over it, if the admin choose to execute the script on the same machine, it becomes localhost. So please don't ask why I'm executing the script on local machine over winrm)

$iisSess = New-PSSession -ComputerName "localhost" -Credential (Get-Credential)
Invoke-Command -Session $iisSess -ScriptBlock { [void][system.Reflection.Assembly]::LoadWithPartialName("System.Net.WebClient") }
Invoke-Command -Session $iisSess -ScriptBlock { $ssrsEndpoint = "http://192.168.10.1/ReportServer/ReportService2010.asmx?WSDL" }
Invoke-Command -Session $iisSess -ScriptBlock { $ssrsProxy = New-WebServiceProxy -Uri $ssrsEndpoint -Credential (Get-Credential) }
Invoke-Command -Session $iisSess -ScriptBlock { $ssrsProxy.CreateFolder("NewFolder", "/", $null) }

`

   + CategoryInfo          : ObjectNotFound: (http://192.168.10...e2010.asmx?WSDL:Uri) [New-WebServiceProxy], WebException
   + FullyQualifiedErrorId : WebException,Microsoft.PowerShell.Commands.NewWebServiceProxy
   + PSComputerName        : localhost
You cannot call a method on a null-valued expression.
   + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
   + FullyQualifiedErrorId : InvokeMethodOnNull
   + PSComputerName        : localhost

It looks like the session didn't get the proper assemblies loaded! Any idea?

Environment

PS C:\deployments\> $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.14409.1005
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14409.1005
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Pretty sure it is not the remoting configurations, see below the command running as a remote command.

[127.0.0.1]: PS C:\Users\Administrator\Documents> winrm get winrm/config
Config
    MaxEnvelopeSizekb = 500
    MaxTimeoutms = 60000
    MaxBatchItems = 32000
    MaxProviderRequests = 4294967295
    Client
        NetworkDelayms = 5000
        URLPrefix = wsman
        AllowUnencrypted = false
        Auth
            Basic = true
            Digest = true
            Kerberos = true
            Negotiate = true
            Certificate = true
            CredSSP = false
        DefaultPorts
            HTTP = 5985
            HTTPS = 5986
        TrustedHosts = *
    Service
        RootSDDL = O:NSG:BAD:P(A;;GA;;;BA)(A;;GR;;;IU)S:P(AU;FA;GA;;;WD)(AU;SA;GXGW;;;WD)
        MaxConcurrentOperations = 4294967295
        MaxConcurrentOperationsPerUser = 1500
        EnumerationTimeoutms = 240000
        MaxConnections = 300
        MaxPacketRetrievalTimeSeconds = 120
        AllowUnencrypted = false
        Auth
            Basic = false
            Kerberos = true
            Negotiate = true
            Certificate = false
            CredSSP = false
            CbtHardeningLevel = Relaxed
        DefaultPorts
            HTTP = 5985
            HTTPS = 5986
        IPv4Filter = *
        IPv6Filter = *
        EnableCompatibilityHttpListener = false
        EnableCompatibilityHttpsListener = false
        CertificateThumbprint
        AllowRemoteAccess = true
    Winrs
        AllowRemoteShellAccess = true
        IdleTimeout = 7200000
        MaxConcurrentUsers = 2147483647
        MaxShellRunTime = 2147483647
        MaxProcessesPerShell = 2147483647
        MaxMemoryPerShellMB = 2147483647
        MaxShellsPerUser = 2147483647

[127.0.0.1]: PS C:\Users\Administrator\Documents>