Use values from old instance for update identifiers

[GoogleCodeExporter]

If modification tracking is enabled and old instance is available use 
those values for identifiers, to enable updating with modified 
identifiers.

Original issue reported on code.google.com by rc.poi...@gmail.com on 3 Jul 2009 at 6:59

[GoogleCodeExporter]

Original comment by rc.poi...@gmail.com on 9 Jul 2009 at 8:09

• Added labels: Priority-Low
• Removed labels: Priority-Medium

[GoogleCodeExporter]

Original comment by rc.poi...@gmail.com on 20 Jul 2009 at 4:28

• Changed title: Use values from old instance for update identifiers