Category removed while updating OffsiteStoreID for a Physical Object

Saravanan_Gurusamy

I have used the following code to update the Offsite Storage ID of a Physical Object. It updates the Offsite Storage ID but it removes the existing category. Any Suggestion ?

Node poNode = docClient.GetNode(ref otAuth, Convert.ToInt64(info.NodeID));
                    AttributeGroup theAttributeGroup = new AttributeGroup();
                    AttributeGroup[] theAttributeGroups = new AttributeGroup[1];

                    theAttributeGroup.Key = "POCreateInfo";
                    theAttributeGroup.Type = "POCreateInfo";

                    StringValue strValue = new StringValue();

                    strValue.Key = "OffsiteStorID";
                    strValue.Values = new string[] { OffsiteId };

                    theAttributeGroup.Values = new DataValue[] { strValue };
                    theAttributeGroups[0] = theAttributeGroup;
                    poNode.Metadata = new Metadata();

                    poNode.Metadata.AttributeGroups = theAttributeGroups;

                    docClient.UpdateNode(ref otAuth, poNode);