Smart Template Issues

Dear All,

          I'm facing below problems in Smart Template,

          1. I Could not found sap:aggregation-role and  sap:required-in-filter properties in gateway.

          2. How to add "Export to Excel" functionality(Button also not visible). Any properties or annotation need to add?

          3. How to display the "Drop down"?

          4. Validation for MultiInput's.

               For ex:- 'Customer' F4 is depends on 'Sales Office'. with out selecting 'Sales Office', if i choose 'Customer' F4 should through error.

          5. Cross Application navigation - How to navigate from my "Sales Order smart template" application to "Delivery" application.

          6. How to concat 2 properties?

I tried to concat CustomerName and CustomerNumber but its not working,

               <Record Type="UI.DataField">

                        <Annotation Term="UI.Importance" EnumMember="UI.ImportanceType/High" />

                        <PropertyValue Property="Label" String="Customer" />

                                <PropertyValue Property="Value">

                                    <Apply Function="odata.concat">

                                    <Path>CustName</Path>

                                        <String>(</String>

                                        <Path>Customer</Path>

                                        <String>)</String>

                                    </Apply>

                                </PropertyValue>

                            </Record>

Thanks and Regards,

Santhosh Gowda