Recently discovered an excellent way to automate versioning of assemblies integrated in a TFS build definition. I followed the guide and instructions written at this code plex open source project
Then I created specific build templates including these options, so that creators and users of build definitions can edit all the versioning attributes a long side other customizations for two of our clients and they are very happy about it.
I really recommend this custom made build activities to all who need to automated assembly versioning included in their TFS build templates and definitions.
Good work guys!