TFS 2010 Work Items (e.g. PBI) - Need to copy current PlainText field values/content to new HTML field

I have a case where I need to copy the contents of a PlantText description field to a new HTML description field.

I was hoping this could simply be done in excel as a copy>paste then published but this doesn't appear to be supported at this time.

Any ideas?

Regards and Cheers

Clint