Packing and unpacking a jar-file?

Question

Hi,
i´ve to write a program, which should read and write jar-files. Does anyone know how to do this?
I´m writing the program with c# and .net-framework 2.0 under Visual Studio 2008 Professional. I tried to use SharpZipLib (http://www.icsharpcode.net/OpenSource/SharpZipLib/Default.aspx) as an external library but that doesn´t work. I was told that jar is a little bit different from normal zip. Can anyone help me please?