How to append files to a splitted archive?

[AlPecin]

When I use this code it works fine:

string ArchiveFile = Path.Combine(Environment.CurrentDirectory, "Archive.7z");

SevenZipCompressor.SetLibraryPath(Path.Combine(Environment.CurrentDirectory, "7z.dll"));
var compressor = new SevenZipCompressor
{
    ArchiveFormat = OutArchiveFormat.SevenZip,
    DirectoryStructure = true,
    PreserveDirectoryRoot = true
   // , VolumeSize = 1000 * 1024 * 10 // 10MB segments
};

// Compress the Files directory
compressor.CompressDirectory(Path.Combine(Environment.CurrentDirectory, "Files"), ArchiveFile);

// Append two files
var modificationList = new List<string>
        {
            Path.Combine(Environment.CurrentDirectory, "EventLog.txt"),
            Path.Combine(Environment.CurrentDirectory, "FileVersions.txt")
        };

compressor.CompressionMode = CompressionMode.Append;
compressor.DirectoryStructure = false;
compressor.PreserveDirectoryRoot = false;

compressor.CompressFiles(ArchiveFile, modificationList.ToArray());

but when I want to get a splitted archive (uncomment the line with VolumeSize) I got a Exception:

Could not pack files! Message: file "...\Archive.7z" does not exist.

What do I have to do to make it work?