Get EPMDocument of children of assembly

I am using Windchill 10.2. I am trying to download assembly as well as its child parts with correct version(Not latest) using JAVA APIs.

Here is the situation -

I created one Assembly A with version 1.1 has 2 parts P1 with version 1.1 and P2 with version 1.1. Now I changed P2 and checked-in assembly again. So assembly version becomes 1.2, P1 is still 1.1 but P2 moves to 1.2.

A (1.1)                              A (1.2)

    |---- P1 (1.1)                         |---- P1 (1.1)

    |---- P2 (1.1)                         |---- P2 (1.2)

Now, I want to download Assembly with version 1.1 and its children, P1 and P2, both having version 1.1. I am doing following to get EPMDocument of assembly.

QuerySpec qSpec = new QuerySpec( EPMDocumentMaster.class );

qSpec.appendWhere( new SearchCondition( EPMDocumentMaster.class, EPMDocumentMaster.NAME, SearchCondition.EQUAL, "abc.asm") );

QueryResult qrMasters = PersistenceHelper.manager.find( qSpec );

QueryResult qr = VersionControlHelper.service.allVersionsOf( (Mastered)qrMasters.nextElement() );

EPMDocument epmDocument;

while ( qr.hasMoreElements() ) {

  epmDocument= (EPMDocument) qr.nextElement(); <-- Here I got EPMDocument of Assembly

  VersionInfo versionInfo = epmDocumentTemp.getVersionInfo();

  if ( versionInfo.getIdentifier().getValue().equals("1") ) {    

      break;

      }

  }

Now I got EPMDocument. I want to know its children. For this,

QueryResult qr = EPMStructureHelper.service.navigateUses(  epmDocument, null, false);

Enumeration enum1 = qr.getEnumeration();

while (enum1.hasMoreElements()) {

    EPMMemberLink aEPMMemberLink = (EPMMemberLink) enum1.nextElement();

}

Here, I want to know EPMDocument of each child of assembly.

When I do,

EPMDocumentMaster aEPMDocumentMaster = (EPMDocumentMaster) aEPMMemberLink.getUses();

QueryResult qr1 = VersionControlHelper.service.allVersionsOf(aEPMDocumentMaster);

EPMDocument doc = (EPMDocument) qr1.nextElement();

I always get document of latest iteration. I want the one that is referenced by assembly of earlier version. How do I find this? I am more interested in knowing its iteration number.