visual studio 2010 add reference version missing

In VS2008 when I add a reference to a dll e.g log4Net I get the following in csproj

<Reference Include="log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821, processorArchitecture=MSIL">
      <SpecificVersion>False</SpecificVersion>
      <HintPath>..\..\lib\log4net\log4net.dll</HintPath>
    </Reference>

In VS2010 when I add a reference to a dll for the first time e.g log4Net I get the following in csproj (i.e no version number etc)

  <Reference Include="log4net">
          <HintPath>..\..\lib\log4net\log4net.dll</HintPath>
   <开发者_如何学Go/Reference>

If I remove reference and add a second time the same details as in VS2008 is there (Version etc)

Anyone know why version number etc not present the first time I add a reference and why it is present on secound time reference added?

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Both snippets are equal - log4net assembly is not fully qualified

This seems to be a problem with the serialization but don't worry it should work

s