How to get resource names for optional content group in a pdf?

Question

I am trying to implement functionality to allow user to add markups to existing layers in a pdf. Here is the code that I am using to draw lines on to a layer in a pdf:

PDResources  resources = page.findResources();
PDPropertyList props = resources.getProperties();        
COSName resourceName = getLayerResourceName("Superimposed3", resources, props);
PDPageContentStream cs1 = new PDPageContentStream(document, page, true, false);
cs1.beginMarkedContentSequence(COSName.OC, resourceName);
cs1.setStrokingColor(0, 0, 255);
cs1.setLineWidth(0.8F);
cs1.drawLine(100,100,250,200);
cs1.endMarkedContentSequence();
cs1.close();

I am using beginMarkedContentSequence instead of beginMarkedContent as I am using pdfbox 1.8 version and 2.0.5 version is not available for .net. Here, is my function to get resource name for a layer:

 private static COSName getLayerResourceName(string layerName,PDResources resources,PDPropertyList props)
        {
            int index = 0;
            COSName resourceName = COSName.getPDFName("MC"+ index);
            PDOptionalContentGroup ocg = props.getOptionalContentGroup(resourceName);
            if (ocg != null && (ocg.getName() == layerName))
            {
                return resourceName;    
            }
            else if (ocg == null)
            {
                return null;
            }
            else
            { 
                resourceName = null;
                index++;
                bool exitFlag = false;
                while (!exitFlag)
                {
                    resourceName = COSName.getPDFName("MC" + index);
                    ocg = props.getOptionalContentGroup(resourceName);
                    if (ocg == null)
                    {
                        exitFlag = true;
                        resourceName = null;
                    }
                    else if (ocg.getName() == layerName)
                    {
                        exitFlag = true;
                    }
                    else
                    {
                        index++;
                    }
                }
            }
            return resourceName;
        }

The above functions only works for those layers which were added using the LayerUtility.appendFormAsLayer function. But it doesn't work for those layers which were created using the following code:

PDOptionalContentProperties ocprops = document.getDocumentCatalog().getOCProperties();
PDOptionalContentGroup newGroup = new PDOptionalContentGroup("Superimposed2");
PDOptionalContentGroup newGroup1 = new PDOptionalContentGroup("Superimposed3");
ocprops.addGroup(newGroup);
ocprops.addGroup(newGroup1);

So, shall I add "MC" value in properties of page myself while, creating layer, or is there another way to get resource name for such layers.