NavigationProperty link doesn't pass key value to related Flow

Hi,

On SCPI Data Data Services I created an Employee OData Service with EmployeeSummary to get all employee id and name, and Employee, to get a specific employee details (odatas1.png).

I have created also association in order to use the feature of NavigationProperty.

This is my EDMX schema:

<edmx:Edmx Version="1.0"
    xmlns:edmx="http://schemas.microsoft.com/ado/2007/06/edmx">
    <edmx:DataServices
        xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" m:DataServiceVersion="2.0">
        <Schema
            xmlns="http://schemas.microsoft.com/ado/2008/09/edm" Namespace="S1">
            <EntityType Name="EmployeeSummary">
                <Key>
                    <PropertyRef Name="key"/>
                </Key>
                <Property Name="id" Type="Edm.String" Nullable="false"/>
                <Property Name="key" Type="Edm.String" Nullable="false"/>
                <Property Name="employee_name" Type="Edm.String" Nullable="true" MaxLength="40" Unicode="true" FixedLength="false"/>
                <NavigationProperty FromRole="EmployeeSummaryRole" Name="EmpRef" Relationship="S1.FK_EmployeeSummary_Employee" ToRole="EmployeeRole"/>
            </EntityType>
            <EntityType Name="Employee">
                <Key>
                    <PropertyRef Name="id"/>
                </Key>
                <Property Name="id" Type="Edm.String" Nullable="false"/>
                <Property Name="employee_name" Type="Edm.String" Nullable="true" MaxLength="40" Unicode="true" FixedLength="false"/>
                <Property Name="employee_salary" Type="Edm.String" Nullable="true" MaxLength="40" Unicode="true" FixedLength="false"/>
                <Property Name="employee_age" Type="Edm.String" Nullable="true" MaxLength="40" Unicode="true" FixedLength="false"/>
            </EntityType>
            <Association Name="FK_EmployeeSummary_Employee">
                <End Multiplicity="1" Role="EmployeeRole" Type="S1.Employee"/>
                <End Multiplicity="1" Role="EmployeeSummaryRole" Type="S1.EmployeeSummary"/>
                <ReferentialConstraint>
                    <Principal Role="EmployeeSummary">
                        <PropertyRef Name="key"/>
                    </Principal>
                    <Dependent Role="Employee">
                        <PropertyRef Name="id"/>
                    </Dependent>
                </ReferentialConstraint>
            </Association>
            <EntityContainer Name="EC1" m:IsDefaultEntityContainer="true">
                <EntitySet Name="Employees" EntityType="S1.EmployeeSummary"/>
                <EntitySet Name="Employee" EntityType="S1.Employee"/>
                <AssociationSet Association="S1.FK_EmployeeSummary_Employee" Name="CN_TO_C_AssocSet">
                    <End EntitySet="Employee" Role="EmployeeRole"/>
                    <End EntitySet="Employees" Role="EmployeeSummaryRole"/>
                </AssociationSet>
            </EntityContainer>
        </Schema>
    </edmx:DataServices>
</edmx:Edmx>

When I call /Employees (odatas2.png flow) I get /Employees('1')/EmpRef reference

<link href="Employees('1')/EmpRef" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/EmpRef"
            title="EmpRef" type="application/atom+xml;type=entry" />
        <content type="application/xml">
            <m:properties>
                <d:id>1</d:id>
                <d:key>1</d:key>
                <d:employee_name>Sevan Haddeler</d:employee_name>
            </m:properties>
        </content> 

then I proceed with the employee details invoking the reference link (eg: /Employees('1')/EmpRef).

Unfortunately I get a not found because the key (id) is not passed to the second flow (odatas3.png flow):

"LoggerScript output":

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<Employee>
   <Employee>
      <id/>
   </Employee>
</Employee>

Where am I wrong?
Thank you in advance.