OData input is not passing to sap gateway deep entity method?

Dear scn members,

I have created create deep entity set method to create PO but item values are not passing. I put break point also. but only passing header item is not passing.

My Input request is like below.

<?xml version="1.0" encoding="utf-8"?>

<entry xml:base="http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/" xmlns="http://www.w3.org/2005/Atom" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices">

  <id>http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/PurchaseOrderSet('4500017736')</id>

  <title type="text">PurchaseOrderSet('4500017736')</title>

  <updated>2016-06-06T10:32:24Z</updated>

  <category term="ZPO_SAMPLE_SRV.PurchaseOrder" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme"/>

  <link href="PurchaseOrderSet('4500017736')" rel="edit" title="PurchaseOrder"/>

  <link href="PurchaseOrderSet('4500017736')/PurchaseOrderItemSet" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/related/PurchaseOrderItemSet" type="application/atom+xml;type=feed" title="PurchaseOrderItemSet">

   <m:inline>

    <feed xml:base="http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/">

     <id>http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/PurchaseOrderSet('4500017736')/PurchaseOrderItemSet</id>

     <title type="text">PurchaseOrderItemSet</title>

     <updated>2016-06-06T10:32:24Z</updated>

     <author>

      <name/>

     </author>

     <link href="PurchaseOrderSet('4500017736')/PurchaseOrderItemSet" rel="self" title="PurchaseOrderItemSet"/>

     <entry>

      <id>http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/PurchaseOrderItemSet(PoItem='00002',PoNumber='4500017736')</id>

      <title type="text">PurchaseOrderItemSet(PoItem='00002',PoNumber='4500017736')</title>

      <updated>2016-06-06T10:32:24Z</updated>

      <category term="ZPO_SAMPLE_SRV.PurchaseOrderItem" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme"/>

      <link href="PurchaseOrderItemSet(PoItem='00002',PoNumber='4500017736')" rel="edit" title="PurchaseOrderItem"/>

      <content type="application/xml">

       <m:properties>

        <d:DispQuan>34.000</d:DispQuan>

        <d:Material>1157</d:Material>

        <d:PoItem>1</d:PoItem>

        <d:PoNumber>4500017736</d:PoNumber>

       </m:properties>

      </content>

     </entry>

     <entry>

      <id>http://DNMECQ.DANAMCONSULTING.COM:8000/sap/opu/odata/sap/ZPO_SAMPLE_SRV/PurchaseOrderItemSet(PoItem='00010',PoNumber='4500017736')</id>

      <title type="text">PurchaseOrderItemSet(PoItem='00010',PoNumber='4500017736')</title>

      <updated>2016-06-06T10:32:24Z</updated>

      <category term="ZPO_SAMPLE_SRV.PurchaseOrderItem" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme"/>

      <link href="PurchaseOrderItemSet(PoItem='00010',PoNumber='4500017736')" rel="edit" title="PurchaseOrderItem"/>

      <content type="application/xml">

       <m:properties>

        <d:DispQuan>34.000</d:DispQuan>

        <d:Material>1157</d:Material>

        <d:PoItem>2</d:PoItem>

        <d:PoNumber></d:PoNumber>

       </m:properties>

      </content>

     </entry>

    </feed>

   </m:inline>

  </link>

  <link href="PurchaseOrderSet('4500017736')/$links/PurchaseOrderItemSet" rel="http://schemas.microsoft.com/ado/2007/08/dataservices/relatedlinks/PurchaseOrderItemSet" type="application/xml" title="PurchaseOrderItemSet"/>

  <content type="application/xml">

   <m:properties>

    <d:PoNumber></d:PoNumber>

    <d:CoCode>3000</d:CoCode>

    <d:DocType>EUB</d:DocType>

    <d:PurchOrg>3000</d:PurchOrg>

    <d:PurGroup>000</d:PurGroup>

    <d:Currency>EUR</d:Currency>

   </m:properties>

  </content>

</entry>

IN ls_data  Item value is not passing only header only passing.

create deep entity code structure is give below

TYPES: ty_t_pr_items TYPE TABLE OF ZCL_ZPO_SAMPLE_MPC=>ts_purchaseorderitem WITH DEFAULT KEY.

TYPES: BEGIN OF ts_purchaseorderitems.

            INCLUDE TYPE ZCL_ZPO_SAMPLE_MPC=>ts_purchaseorder.

TYPES: PrItemCollection TYPE ty_t_pr_items,

           END OF ts_purchaseorderitems.

DATA: ls_data TYPE  ts_purchaseorderitems.

io_data_provider->read_entry_data( IMPORTING es_data = ls_data ).

*    ls_item-PRItemCollection  = ls_data-PrItemCollection.

lt1_items  = ls_data-PrItemCollection.

please help me on this but  in odata create deep entity is created successfully but Po is not created because in ITem table is passing empty value.