Help: Need to retrieve SharePoint document records for a given Opportunity

Hello,

So I thought this would be easier than I am having :-) it be.

I have an opportunityid. That opportunity has several documents loaded. I need an example please of how exactly to retrieve the SharePoint documents related too it, so I can grab the details about those documents.

However, for some reason I can't see to get the details.

*Simple Check. I tried to retrieve all the SharePoint document records but it returns 0 entity records, even though there are in fact 7 document locations and I added 3 documents, which do come up in the UI under that opportunity.

I would be very grateful for very specific code related help, a link is fine too, but I've not found one with actual code for doing it.

I figured I needed to use the relationship Opportunity_SharepointDocument, but I just get a server 500 error.

Here is that code

QueryExpression query = newQueryExpression();

query.EntityName = SharePointDocument.EntityLogicalName;

query.ColumnSet = newColumnSet(true);

Relationship relationship = newRelationship();

relationship.SchemaName = "Opportunity_SharepointDocument";

RelationshipQueryCollection relatedEntity = newRelationshipQueryCollection();

relatedEntity.Add(relationship, query);

RetrieveRequest request = newRetrieveRequest();

request.RelatedEntitiesQuery = relatedEntity;

request.ColumnSet = newColumnSet(true);

request.Target = newEntityReference { Id = newGuid("myopptyhere"), LogicalName = Opportunity.EntityLogicalName };

RetrieveResponse response = (RetrieveResponse)_sourceServiceProxy.Execute(request);

//get's back an "unexpected error"

Is this code at least correct and maybe the server has an issue or my sharepoint config?