Web Dynpro - Save Metadata problem

Hi,

I am using the new 6.40 sneak preview and have created a basic web dynpro application. When I go into the source code that is generated by the GUI tools and make a manual change then click on Save Metadata, all the code is commmented out and then naturally I get lots of compile errors? Is this a known bug? Is there a solution?

Thanks in advance,

Simon