PsiReference to an XML file

Hi

I'm implementing a reference contributor for a custom XML. I am trying to find if the custom xml file is being referenced in any of the other xml files

<RowIterator
  elementName="name"
  pickLocation="NewPerson.push()"/>

This code is in one xml file called Main.myxml. And then NewPerson.myxml is another file

Objective: When I do find usages of NewPerson.myxml, I should be able to find its usage in Main.myxml i.e. Main xml should come in the results

I am implementing the contributor. Here is the code

<psi.referenceContributor implementation="com.abc.search.CustomXmlReferenceContributor"/>

public class CustomXmlReferenceContributor extends PsiReferenceContributor {
  @Override
  public void registerReferenceProviders(@NotNull final PsiReferenceRegistrar registrar) {


    registrar.registerReferenceProvider(PlatformPatterns.psiElement(XmlTag.class),
            new PsiReferenceProvider() {
              @NotNull
              public PsiReference[] getReferencesByElement(@NotNull PsiElement element, @NotNull ProcessingContext context) {
                XmlTag tag = (XmlTag) element;
                XmlAttribute attribute = tag.getAttribute("pickLocation");
                if (attribute == null) {
                  return PsiReference.EMPTY_ARRAY;
                }
                String attributeValue = attribute.getValue();
                System.out.println(attributeValue);
                System.out.println(element.getContainingFile());

                int i = attributeValue.indexOf(".push");
                if (i != -1) {
                  attributeValue = attributeValue.substring(0, i);
                }

                PsiFile[] files = FilenameIndex.getFilesByName(element.getProject(), attributeValue + ".myxml", ProjectScope.getProjectScope(element.getProject()));

                if (files.length == 0) {
                  return PsiReference.EMPTY_ARRAY;
                }

                String finalAttributeValue = attributeValue;
                return new PsiReference[]{new PsiReference() {
                  public PsiElement getElement() {
                    return tag;
                  }

                  public TextRange getRangeInElement() {
                    final int start = tag.getTextRange().getStartOffset();
                    return tag.getValue().getTextRange().shiftRight(-start);
                  }

                  @Nullable
                  public PsiElement resolve() {
                    return files.length > 0 ? files[0] : null;
                  }

                  @NotNull
                  public String getCanonicalText() {
                    return finalAttributeValue;
                  }

                  public PsiElement handleElementRename(String newElementName) throws IncorrectOperationException {
                    throw new UnsupportedOperationException();
                  }

                  public PsiElement bindToElement(@NotNull PsiElement element) throws IncorrectOperationException {
                    throw new UnsupportedOperationException();
                  }

                  public boolean isReferenceTo(PsiElement element) {
                    return resolve() == element;
                  }

                  public Object[] getVariants() {
                    return null;
                  }

                  public boolean isSoft() {
                    return false;
                  }
                }
                };
              }
            });

  }
}

But this does not work. What am I missing? I would really appreciate any help or tip how this whole thing works..

Thanks in advance!