SCSM SDK Relating an Incident to a File Attachment

Question

It seems that I have too many Exchange Connectors so I am looking to find other avenues to meet the needs of my users.  I was planning on trying to pitch using Self-Service Portal for internal requests and creating an website for external client requests.
While I was able to create and Incident and a File Attachment via the SDK and C#, the process failed when I tried to create the relationship between them.  I've tried to find an answer on the internet but I am coming up short.  I followed the examples
correctly but the code fails with a DiscoveryDataLifetimeDependencyException
public static void Test_AttachFileToWorkItem()
EnterpriseManagementGroup mg = new EnterpriseManagementGroup("scsmserver");
EnterpriseManagementObject createdIncident = mg.EntityObjects.GetObject<EnterpriseManagementObject>(new Guid("9AF45443-150E-2AE4-B4F5-CC76930ED3F8"), ObjectQueryOptions.Default);
EnterpriseManagementObject fileAttachment = mg.EntityObjects.GetObject<EnterpriseManagementObject>(new Guid("4FFEBC8B-C1CF-27D5-E01C-CD8E22A06873"), ObjectQueryOptions.Default);
ManagementPackRelationship relAttachment = mg.EntityTypes.GetRelationshipClass(new Guid("aa8c26dc-3a12-5f88-d9c7-753e5a8a55b4"));
CreatableEnterpriseManagementRelationshipObject attachmentRelationship = new CreatableEnterpriseManagementRelationshipObject(mg, relAttachment);
attachmentRelationship.SetSource(createdIncident);
attachmentRelationship.SetTarget(fileAttachment);
attachmentRelationship.Commit(); //Error here

Answer 1

i may be reading this wrong, but it looks like you are trying to create a relationship for a file attachment object that already exists. this will never work.
the relationship for file attachments is like the relationship for WorkItemContainsActivity. the lifetime of the child object is linked to the lifetime of the relationship. if the relationship is deleted, the child object is similarly deleted. the corollary
of this is that if you create an object in the database without this relationship, it can never be added to a relationship. 
instead of using mg.EntityObjects.GetObject() to get an existing object, Create the object using CreatableEnterpriseManagementObject inline, populate it with data, but do not commit it. create your relationship using the same code you specify here,
using the variable holding your uncommitted file attachment object in the relationship, then commit only the relationship object. 
for reference, here is similar powershell i used to do this: 
$FileParams = @{
Extension = ".xml"
Description=$FileName
Content = $SourceFile
Size = $SourceFileSize
AddedDate = (get-date).ToUniversalTime()
DisplayName = $FileName
ID=([System.Guid]::NewGuid()).ToString()
#create the attachement, then create the relation, then submit them both in one go.
$FileToAttach = New-SCSMObject -Class $fileClass -PropertyHashtable $FileParams -nocommit
$NewfileRelation = New-SCSMRelationshipObject -Relationship $AttachedFile -Source $Cr -Target $FileToAttach -nocommit
$NewFileRelation.commit()