If you look through the code you'll see that Iso8583.MsgType._0800_NWRK_MNG_REQ
is a constant int 0x800. I recommend that you create your own Iso8583Rev03
message and your own subclass MsgType where you put
public const int _2800_NWRK_MNG_REQ = 0x2800;
Then use that in your code.