[V8i C#] Setting model scale when attaching to sheet

Hi All,

I'm generating an A1 sheet view of a model and having difficulties setting the scale.  After running the below code and open the model in Microstation it is 1:1, not 1:250 as I want it.  If I reload the file and inspect the attachment in code the scale factor has not saved.  

            var attachments = microstationapp.ActiveModelReference.Attachments;
            attachments.AddUsingNamedView1(defaultprojectfile, "Model", "FullView", "Main view of conveyor", "Front", startlocation, MsdAddAttachmentFlags.msdAddAttachmentElementsVisible);
            //attachments.Add(defaultprojectfile, "Model", "FullView", "", originlocation, startlocation, true, true);

            var attachment = microstationapp.ActiveModelReference.Attachments.FindByLogicalName("FullView");
            attachment.AttachmentScaleFactor = 0.0004;
            attachment.ScaleFactor = 0.0004;

Things I've checked so far:

It's defs calling Save() and Close() afterwards, and I've inspected a reference in code that I manually added in a model and and tried to make all the properties the same.

I'd appreciate any help you can give on this, thanks.