XMA/ECMA call-based export does not support multi-valued attribute-level deltas

Here's a seemingly undocumented feature of the XMA/ECMA. I've got an XMA that's doing call-based exports, and I've noticed that it doesn't contain atomic add & remove operations at the item level in a multi-valued attribute list. Instead, it's giving me the entire list of items in the object's current state.

This is interesting, because when I look at the pending export in the sync engine, I see the atomic operations.

When I examine the arguments passed into the ExportEntry API call, I see a Replace at the top level, but nothing on the multi-valued attribute (member in this case).

[ExportEntry]

modificationType:   Replace      
changedAttributes:  member
csentry:            [Microsoft.MetadirectoryServices.Impl.CSEntryMAImpl] CS Role CN=ROLE-CRM-Test1
DN:                 CN=ROLE-CRM-Test1
ObjectClass:        Microsoft.MetadirectoryServices.Impl.GenericValueCollection
ObjectType:         Role         
RDN:                CN=ROLE-CRM-Test1
displayName         [String]            ROLE-CRM-Test1
member              [Reference]         CN=007528
                                     CN=dev.userA
                                     CN=dev.userB
                                     CN=dev.userC
                                     CN=dev.userD
                                     CN=dev.userE
                                     CN=dev.userF

(Wouldn't it be nice if you could just serialize the CSEntry object?)

So, I looked around on the forums, and sure enough, Markus confirms my observation:

"If members is in the list of changed attributes, the member attribute of the CSEntry contains the most recent value for this attribute.

"If you need to determine the individual change for each member, you need to calculate this. The ECMA doesn’t provide multi-valued attribute level changes."

Rebecca Croft also informs me that not even the file-based export supports item-level deltas on multi-valued attributes.

I'd love to be proven wrong about this...