Copy a file except for the first line in MSBuild

Question

I have an automatically generated file (generator not created by me) which, as its first line, contains the date when it was generated. To simplify my life with Subversion, I want to create a version of this automatically generated files which does not contain this first line.

My guess Is I have to do something like

<ReadLinesFromFile File="SomeTempFileThatIRedirectedMyToolToOutput.cs">
    <Output TaskParameter="Lines" ItemName="AllLines"/>
</ReadLinesFromFile>
<SomeMagicTaskThatRemovesTheFirstItem Input="@(AllLines)">
    <Output TaskParameter="Output" ItemName="LinesExceptFirst"/>
</SomeMagicTaskThatRemovesTheFirstItem>
<WriteLinesToFile File="RealOutputFile.cs" Lines="@(LinesExceptFirst)" Overwrite="true"/>

But what should I use for my magic task?