Problem with relative paths in VS 2010

We have migrated to Visual Studio 2010, but have problems with relative paths (that is when selecting a file in Solution Explorer and showing File Properties).

The problem is when using environment variables to specify paths. This works fine in Visual Studio 2005 and even when migrating to 2010 the relative paths are kept for existing files. But when including new files and trying to set the relative path the environment variables are not parsed correctly.

For example, if the relative path is set to:

$(PATH)/history.cpp

When pressing enter, it's immediately replaced with

%2524%2528PATH%2529\history.cpp

In Visual Studio 2005, the full path is at the same time changed to C:\NEW_PATH\history.cpp (depending on the environment variable PATH on each computer, in this case "C:\NEW_PATH"). But in VS 2010 the relative path is only appended to the end of full path like this:

C:\Project\HTT\$(PATH)\history.cpp

which is useless when using enviroment variables. Is this a bug? Any workaraound available? Please help, we really need this flexibility because paths are very different on many development computers we have.